Paleontological Bulletin, No. 34. 
CONTRIBUTIONS 
TO THE 
HISTORY OF THE VERTEBRATA 
OF THE 
LOWER EOCENE OE W10MING DIO NEW MEXICO, 
MADE DURING 1881. 
By IE. ID_ COPE. 
(.Extr. Am. Phil. Soc.) 
(Read before the Amer. Philosophical Society, Dec, 16, 1881.) 
FOR SALE BY A. E. FOOTE, 
imS BELMONT AVENUE, 
PHILAEEL mX-iV. 1881.] 
139 
[Cope. 
Contributions to the History of the Vertebrata of the Lower Eocene of 
Wyoming and New Mexico, made during 1881. By E. D. Cope. 
(Read before the American Philosophical Society, Dec. 16, 1881.) 
I. The Fauna of the Wasatch Beds of the Basin of the Big 
Hokn River. 
The basin of the Big-Horn river contains the most northern area of the 
deposits of the Wasatch or Suessonian epoch known. In order to ascer- 
tain whether the fauna it contains differs in any way from that I discov- 
ered in the corresponding beds of New Mexico in 1874, I sent, during the 
past season, an expedition, under the direction of J. L. Wortman, already 
known from his successful exploration of the Wind River basin in 1880. 
The present paper gives a review of the results of the season’s work, pre- 
faced by an account of the geology furnished by Mr. Wortman. The 
species herein described are being engraved for the fourth volume of Dr. 
Hayden’s report of the United States Geological Survey of the Territories, 
now passing through the press. 
As early as 1859 Dr. Hayden described in detail the Tertiary sediment 
occupying the upper drainage basin of the Big-Horn river, which he deter- 
mined as belonging to the lower Eocene formation, and applied the name 
Wind River group, from its being exposed along the Wind river, a name 
given to the upper portion of the Big-Horn. From an extensive collec- 
tion of vertebrate fossils made by the writer at this horizon, during the 
summer of last year, Prof. E. D. Cope, for whom the collection was made, 
has, in a bulletin, U. S. Geol. Surv. Terrs., F. V. Hayden, Vol. vi, No. 
1, 1881, confirmed this determination, and discussed at length the faunal 
relations they bear both to the Bridger and Wasatch beds respectively. 
The conclusions reached are, that this series is intermediate to a certain 
degree, containing genera hitherto regarded as peculiar to each. This 
upper basin covers quite an extensive area, and is bounded upon every 
side by lofty mountains. The Owl Creek mountains, which afforded a 
barrier to the waters of this Eocene lake on the north, has subsequently 
been cleft by the Big-Horn, leaving a deep and rough canon, through 
which it now Hows in its course north to the Yellowstone. After passing 
the Owl Creek mountains it emerges into a second or lower basin, com- 
monly called the Big-Horn basin proper. This one covers a much larger 
area than the upper, and like it is walled in by mountain ranges, 
and filled with a mass of sedimentary rock which is also referable to the 
lower Eocene series. 
During the summer of the present year the writer has been engaged in 
further exploration of this interesting region, which resulted in the col- 
lection of a large number of extinct vertebrates, obtained exclusively from 
the lower Eocene horizon of the Big-Horn, and which have all been sub- 
1. The Geology of the Big-Horn Busin, by Jacob L. Wortman. Cope.] 
140 
[Dec. 16, 
mitted to Prof. Cope, at whose instance the party was organized and 
equipped. 
Dr. Hayden has made the observation that upon the eastern slope of the 
Wind River mountains all the corresponding strata are visible from the 
Silurian to the Ci’etaceous; this is also true of the northern slope of the 
Owl Creek mountains, while the southern side does not exhibit such con- 
tinuity of structure. Upon entering the basin from the south, the older 
formations are seen to extend towards its centre for a distance of ten miles, 
inclining at an angle of 30° to the north, while the level of the Tertiary 
lias been little or not at all disturbed since its deposition. That this 
basin contained a separate and isolated body of water, limited by its pres- 
ent boundaries, which were outlined about the beginning of the Wasatch 
epoch, there is every reason to believe. A section made by the Big-Horn 
at the southern extremity shows the Tertiary to rest unconformably upon 
a thick mass of buff colored sandstone, rather coarse in texture, somewhat 
laminated, and towards the bottom interspersed with thin layers of im- 
pure lignite varying from six inches to one foot in thickness. This sand- 
stone most probably belongs to the Laramie series, but in the absence of 
fossils the determination is by no means satisfactory. 
The Eocene sediment covers a large part of the basin, and cannot be 
less than 4000 feet in vertical depth. This mass, once continuous over a 
large area, has since been carved and weathered into many fantastic and 
remarkable forms, presenting at once a bold and striking appearance, a 
characteristic feature of the western Tertiary bad lands. 
Beginning at the southern limit at a point opposite the mouth of Meyers 
creek, on the east side of the river, a series of low bad land bluffs, facing 
to the west and gradually becoming higher as they proceed, describe a 
gentle curve to the north, terminating at the river’s edge 30 miles below. 
The character of the country between the river and these bluffs is a barren 
sage brush plain, while back of the bluffs a high mesa occupies the coun- 
try for many miles. On the west side, numerous rivers, creeks, and their 
tributaries, putting down from the Sierra Shoshone range, have excavated 
the mass in every direction, leaving bold escarpments, high bad land buttes, 
elevated tables, with innumerable gulches and ravines. Country of this 
character stretches far away to the northern limit, near the Big Horn gap, 
presenting that desolate and sombre appearance, so often met with in bad 
land regions, 
Its composition may be described as consisting of various colored clays 
alternating with lasers of brown and blue sandstone, although that even- 
ness of stratification by which a single layer of either, in one part, could 
be identified in another, does not exist. Those exposures, for example, on 
the east side of the Big-Horn are highly arenaceous, the clay and sand 
existing in almost equal proportions, while in the exposures along the 
Grey Bull river, and in the vicinity of Coryphodon butte, the quantity of 
sand is greatly diminished, and is found in separate layers. The prepon- 
derance of the red clay is a marked feature, and has called forth the 1881.] 
141 
[Cope. 
remark from Dr. Hayden, relative to the sediment of the upper basin, 
“that they remind one of the Jura Trias red beds.’’ This remark is forci- 
bly illustrated by the character of the sediment found in the south-western 
part of the basin, near the head of Gooseberry creek, where the exposures 
consist largely of thick strata of the red clay, which gradually thin out to 
the north and east, blending with the pink, blue, and buff colors. In the 
northern part of the basin, and along Stinking river, the sediment consists 
almost exclusively of a pale yellow sandstone of a bluish tinge, from which 
few fossils "were obtained. 
The clays contain much lime in the form of small limestone nodules of 
a rusty brown appearance, in which the fossils are often found, having a 
thin and intensely hard layer of ferrous oxide investing them externally. 
In the red the fossils are always scarce and fragmentary, and when found 
are usually such parts as would, under the most favorable circumstances, 
he preserved. The blue seems to be the more productive, and to have 
offered better conditions for their preservation ; but, owing to the fact that 
lime forms the petrifying base, and being less able to withstand the heavy 
pressure than many other materials, the fossils from both the red and the 
blue are, as a general rule, greatly distorted and crushed. This fragmen- 
tary occurrence of fossils in the fine-grained clay, I am inclined to believe, 
is due, not to a scattering of the bones by currents, hut rather to imperfect 
and unfavorable conditions for their preservation. That entire skulls and 
skeletons were deposited, where now nothing but the teeth remain, I am 
•well satisfied from the circumstance that both superior and inferior series 
are not unfrequently found in proper position without a trace of ramus or 
cranium. In the sandstones, however, the fossils are in a magnificent 
state of preservation, hut their extreme scarcity in this material gives the 
collector many long and fruitless searches. Two skeletons which have 
proven of considerable interest were all of any consequence that were 
obtained from the sandstones. 
The general stratigraphical appearance, as well as the scattered and 
fragmentary condition of the fossils, together with the community of a 
large number of genera, refer it to the Wasatch epoch, hut a full discus- 
sion of this point belongs properly to the paleontologist. A thorough 
elucidation will be found in Prot. Cope’s paper on the fossils. 
The exploration of this region is most arduous and difficult. The great 
scarcity of water in these bad land wastes, makes it very inconvenient, 
and renders it necessary to carry a water supply a distance of often 20 
miles or more. Even when water does exist it is so strong with alkali as 
to be scarcely fit for use. Many of the streams coming down from the 
mountains dry up as soon as the snow has melted from the low 
foot hills in early spring, leaving large tracts entirely destitute of water, 
which frequently abound in fossiliferous exposures, and which it is the 
object of the explorer to examine. The broken and mountainous charac- 
ter of the country forbids the use of wagons to such an extent that pack 
animals are indispensable. 142 
Cope.] 
[Dec. 16, 
The accompanying map is intended to illustrate the exact position, as 
well as the extent of country covered by the Wasatch sediment at this 
point. Its topography is taken from a map made by Capt. J. Russell, 
Third Cavalry, U. S. A. (and published by the War Department), during 
a reconnoissance of that region in the summer of 1880, and to whom, as 
well as Dr. W. II. Corbusier, Col. J. W. Mason, and other officers sta- 
tioned at Fort Washakie, I wish to express my deep sense of obligation 
for their very kind and courteous treatment. 
Aiup ol the iiiy-llorii liusm, reduced lroiu the Map of the U. S. War Depart- 
ment. 
2. Synopsis of the Fauna. 
Ci.astes sp. ; not abundant. 
Pappichthys sp. Vertebrae ; not very common. 
PISCES. 143 
1881.] 
[Cope. 
REPTILIA. 
Ckocodilus sp. Allied to the C. chamensis and C. heterodon, but not 
represented by sufficiently well preserved specimens to permit of determi- 
nation. There are numerous molariform teeth in the posterior parts of 
jaws, and the crowns of the longer teeth are grooved. Not uncommon. 
Emys sp. Rare ; one specimen of 220 mm. in length, of the type of 
E. vyyomingensis, but not sufficiently well preserved for determination. 
As the Eocene forms of this order are of unusual interest, I give an 
analysis of the extinct genera of the Cryptodire division of tortoises which 
have been found in North America up to the present time. 
In the check-list of the North American Batraehia and Reptilia,* I enu- 
merated nine families of this division of the Testtidinata, three of which 
are extinct. Subsequently another extinct family, the Baenidse, was 
added. I now define all of these families. 
I. Plastron not articulated to the carapace, but presenting to it more or 
less open digitations. Dactylosterna. 
Phalanges of anterior limb without Condyles, and covered by a common 
integument; eight pairs of costal bones Cheloniidce. 
Phalanges of anterior limb without condyles ; nine or more costal bones, 
Propleuridce. 
Phalanges of anterior limb with condyles ; digits inclosed in distinct in- 
teguments ; eight costal bones ; sternal elements united by digitations 
and inclosing fontanelles ; caudal vertebrae procoelous... Trionychidce. 
Phalanges of anterior limbs with condyles ; digits distinct ; eight costal 
bones ; sternal elements united by suture and inclosing no fontanelles ; 
caudal vertebrae opisthocoelous Chelydridm. 
II. Plastron uniting with the costal bones of the carapace, by denticu- 
late suture, and by ascending axillary and inguinal buttresses. (Feet 
ambulatory.) Clidosterna. 
A. Intersternal bones present. 
No intergular scuta Pleurostemidce. f 
Intergular scuta ; caudal vertebrae opisthocoelous Ba'etiidce. 
AA. No intersternal bones. 
a. Intergular scuta. 
A mesosternal bone „ Adocidce. 
aa. No intergular scuta. 
A mesosternal bone ; three series of phalanges Emydidce. 
No mesosternal bone ; three series of phalanges Cinostemidce. 
A mesosternal bone ; two series of phalanges Testudinida. 
* Bulletin U. S. National Museum, No. 1, 1875. p. 16. 
t There are two genera of this family, neither ot them yet found in America ; 
Pleurosternum Ow., with smooth shell, and Helochelys Myer, with sculptured 
shell. 144 
Cope.l 
[Dec. 16, 
III. Plastron uniting with the marginal bones of the carapace by straight 
contact only. (Feet ambulatory.) Lysosterna. 
No intersternal bone nor intergular scutum ; a mesosternal bone and three 
series of phalanges Cistudinidce. 
The extinct species of the Cryptodira of this continent belong to eight of 
the above families. I give diagnoses of the genera to which they are 
referred. Names of existing genera are in Roman type. 
CHELONIID.E. 
Postabdominal bones distinct from each other Chelonia Brong. 
Postabdominal bones united with each other by suture.. Puppigerus Cope. 
Cope.* 
Transactions of American Philosophical Society, xiv., 1870, p. 285. 
Ten costal bones; first two marginals united with carapace by suture; 
shell smooth, flattened Osleopygis Cope. 
Nine costal bones ; first two marginals united to carapace by suture ; shell 
sculptured (a high dorsal keel) Peritresius Cope. 
Nine costal bones ; one marginal united with carapace by suture ; second 
by costal gomphosis ; shell not keeled nor sculptured 
Propleura Cope. 
’Nine costal bones ; first united with carapace by suture ; second without 
costal gomphosis ; shell not sculptured Gatapleura Cope. 
? Nine costal bones ; marginals all free ; shell not sculptured 
Lytoloma Cope. 
Trionychid^e. 
a. Surface of bones smooth. 
Postabdominal suture digitate . Axestus Cope. 
aa. Surface of bones sculptured. 
/9. Sutures of plastron digitate. 
A dermal flap protecting posterior legs below ; marginal bones 
Emyda Gray. 
A dermal flap ; no marginal bones Cyclanosteus Peters. 
No dermal flap nor marginal bones ; muzzle much abbreviated 
• Chitra Gray. 
No dermal flap nor marginal bones ; muzzle elongate... .Trionyx Geoffr. 
Suture for postabdominal coarsely serrate. 
Postabdominal recurved in front Plastomenus Cope. 
a. Bridges of plastron wide ; ? caudal vertebrae. 
One row of marginal scuta ; six pairs of scuta of the plastron 
Idiochelys Myr. 
Chelydrid^e. 
* Palceochelys novemcostatus Geoffr., belongs to this family, but not Palato- 
chelys Myr. 145 
1881.1 
TCope. 
One row of marginal scuta ; scuta of plastron? not distinct 
Hydropelta * Myr. 
aa. Bridges of plastron very narrow. 
/5. Carapace smooth, not sculptured. 
Two rows, of marginal scuta ; five pairs of scuta of the plastron 
Macrochelys Gray. 
One row of marginals ; five pairs on plastron Chelydra Schw. 
One row of marginals ; four pairs of scuta on plastron Claudius Cope. 
ftp. Carapace sculptured. 
Qne row of marginal scuta Anostira Leidy. 
Baenid^e. 
Cope, Annual Report U. S. Geol. Surv. Terrs., 1872 (1873), p. 621. 
Supramarginal scuta (Riitimeyer) ; no interhumerals Platychelys Myr. 
No supramarginals nor interhumeral scuta Buena Leidy. 
No supramarginals ; interhumeral scuta present Polythorax f Cope. 
Cope, Proceedings American Philosophical Society, 1870, p. 559. 
a. Vertebral bones and scuta normal. 
One intergular scutum entirely separating the gulars Adorns Cope. 
Either two intergulars, or the gulars meeting behind intergular 
. Amphiemys Cope. 
aa, Vertebral bones wedge-shaped, widening upwards ; vertebral 
scuta not wider than the bones. 
Elements of carpace early coossified.. .Homorhophus Cope. 
Adocidce. 
Emydidce. 
a. No scutal sutures. 
Surface sculptured Apholidemys Pom. 
aa. Scuta including intermarginals and two anals. 
Lobes of sternum narrow Dermatemys Gray. 
Lobes of sternum wide. Agomphus Cope. 
aaa. Scuta ; two anals, no intermarginals. 
Surfaces of carapace sculptured; plastron fixed Compsemys Leidy. 
Surfaces of carapace smooth ; plastron fixed ; recent Emydidce and the 
genus Emys Brong.| 
Posterior lobe of plastron movable ; surface smooth Ptychogaster Pom. 
Anterior and posterior lobes of plastron movable ; surface smooth 
Dithyrosternum Piet, et Ilumb. 
aaaa. Scuta ; one anal, no intermarginals. 
Carapace smooth Stylemys Leidy. 
* Eurysternum tVagn. (Palccomedusa et Acichelys Myr. (fide Rtttlmeyer) is 
nearly allied to Hydropelta.) 
fPossibly one of the Adocidce; see Proceed. Acad. Phila., Oct., 1876. 
J Gray has distinguished several good genera among existing species on 
cranial characters. Cope.] 
146 
(Dec. 16, 
TESTUDINIDvE. 
a. Two anal scuta. 
Ten abdominal scuta Hadrianus Cope. 
aa. One anal scutum. 
Lower jaw Avith two cutting edges Xerobates Agass. 
LoAver jaw with one cutting edge Testudo Linn. 
RODENTIA. 
Plesiarctomys buccatus Cope. 
Two mandibular rami. 
Plesiarctomys delicatior Leidy. 
Mandibles of six individuals, some of them accompanied by bones of 
the skeleton. 
BUNOTIIERIA. 
T.eniodonta. 
Additional material gives the following results with regard to the 
affinities of this sub-order. There are three allied groups represented by 
the genera Esthonyx, Tillotherium and Calamodon of the American Eo- 
cenes, -which are equally unlike each other. Esthonyx, as I long since 
showed, is related to the existing Erinaceus ; very nearly indeed, if the 
dentition alone is’ considered. Its anterior incisor teeth are unusually 
developed, and have, as in Erinaceus, long roots. One pair at least in the 
lower jaw has enamel on the external face only, and enjoys a considerable 
period of growth. The genus Tillotherium is (fide Marsh) quite near to 
Esthonyx. Its molars and premolars are identical in character with those 
of that genus, the only important difference being found in the incisors. 
Here, one pair above, and one pair below, are faced Avith enamel in front 
only, and grow from persistent pulps as in the Bodentia. This character 
has been included by Marsh in those he ascribes to his “order” of Tillo- 
dontia, but as he includes Esthonyx in that order,* which does not possess 
the character, it is not very clear on what the supposed order reposes. The 
rodent character of the incisors is the only one that I know of which dis- 
tinguishes Tillotherium from the Inesctivora. I have on this account 
retained the Tillodonta as a suh-order, and referred Esthonyx to tlie Insecti- 
rora. 
The Tceniodonta agree with the Tillodonta in the possession of a pair of 
inferior incisors of rodent character, but it adds several remarkable pecu- 
liarities. Chief among these is the character of the inferior canines. In 
the Tillodonta they are either wanting, as in Erinaceus, according to the 
Cuvierian diagnosis, or they are insignificant. In Calamodon they are of 
large size, and though not as long-rooted as the second incisors, groAv from 
presistent pulps. They have two enamel faces, the anterior and the 
posterior, the former like the corresponding face of the rodent incisors. 
* Report of IT. S. G. Survey 40th Parallel, by Clarance King; Vol. i, p. 377. 1881.] 
147 
[Cope. 
The function of the adult crown is that of a grinding tooth. This charac- 
ter distinguishes Calamodon as a form as different from Tillotherium, as 
the latter is from Esthonyx. There are, however, other characters. The 
external incisors, wanting in Tillotherium, are here largely developed, and 
though not growing from persistent pulps have but one. an external band- 
like enamel face. Their function is also that of grinders. 
The fact that the rodent teeth in the lower jaw are the second incisors, 
renders it probable that those of the Tillodonta hold the same position in 
the jaw. This is to be anticipated from the arrangement in Esthonyx, where 
the second inferior incisors are much larger than the first and third. The 
superior dentition of the Tceniodonta is yet unknown. 
Calamodon simpi.ex Cope. 
Report Vertebrate Foss., New Mexico, U. S. Geog. Surv. W. of 100th 
Mer. 1874, p. 5. Report of do. Capt. G. M. Wheeler, iv, ii, p. 166. 
A nearly complete mandible of this species was found by Mr. Wortman, 
besides a series of unworn molar and canine teeth of a second individual, 
and fragments of some others. These furnish the correct dental formula 
as far as they go, as follows : I. 8 ; C. 1 ; M. 5. It appears that I correctly 
referred the long rodent teeth to the lower incisior series, but that the 
truncate two banded teeth so characteristic of the sub-order, are canines 
and not incisors, and that they belong to the lower as well as probably to 
the upper jaw. 
The characters of the incisors are very peculiar. The first are small 
with short subcylindric crowns, and conic roots. The second incisors 
have been described ; as in C. arcammius they have a horizontal shoulder 
posterior to the base of the cutting portion. The third incisors increase 
in diameter upwards, and have a triangular section. The largest side 
of the triangle is interior, and the shortest the posterior, and neither 
possess any enamel. The anterior or enamel faced side is slightly convex. 
The grinding face is transverse and is in the plane of the corresponding 
face of the canine. The long diameter of the crown of the canine is at 
right angles to the anterior face of the third incisor, and diagonal to the 
long axis of the mandibular ramus. This, with the peculiarities of the 
other incisors, gives an irregular appearance to the anterior dentition. 
The five molars are very similar in character, and even those with un- 
worn crowns do not present any distinction into premolars and true 
molars. The enamel covers the summit of the crown, but on wearing, it 
is soon reduced to a cylindrical sheath. Further wear brings the grinding 
surface to the anterior and posterior surfaces which are covered with 
cementum instead-of enamel. 
Insectivoua. 
Esthonyx buhmeisteki Cope. 
Report Vertebrate Foss., New Mexico, 1874, p. 7. Report IT. S. G. G. 
Surv. W. of 100th Mer. G. M. Wheeler, iv, ii, p. 15G, pi. xi, fig. 26. Cope.] 
148 
| Dec. 16, 
Two fractured crania exhibit the entire dentition of this species, and 
give the generic characters satisfactorily. The dental formula is, I. § ; 
C. ; P-m. IE; M. f. The first superior incisor is large, and the crown is 
somewhat spoon-shaped. The second incisor is as robust as the first, but 
the crown is shorter. The second premolar has one external and one in- 
ternal lobe, in the third (fourth) premolar these lobes are much enlarged, 
and the tooth is transverse. The true molars have two external cusps, 
which are flattened, close together, and well within the margin of the 
base of the crown. There is one internal lobe and a strong posterior 
ledge, as in the opossums. Of the inferior incisors, the median is large 
and half gliriform, while the first and third are small. The inferior, like 
the superior canines, are large. The first and second (third) premolars 
have no internal lobes, but the second (third) has a heel. The fourth is 
more or less like the first true molar. 
The specimens show that my original determinations of the incisors 
based on loose teeth were correct. They also show that this genus is not 
far removed from the more rodent-like genus Anchippodus of Leidy. 
There are several species of the genus, which I define as follows : 
I. Fourth inferior premolar like first true molar. 
Larger ; third superior premolar larger; fourth premolar with the external 
cusp bilobate E. acutidens. 
Medium ; third superior premolar smaller ; fourth, premolar with external 
cusp simple; superior incisors wide; large inferior narrower 
E. burmeisleri. 
Medium ; superior incisors narrow ; large inferior wider.... E. bisulcatus. 
IT. Fourth inferior premolar with anterior V open and cutting. 
Smallest ; incisors unknown E. acer. 
A species of the size of E. acer has been named E. spatularius, hut I 
cannot place it in the above key, as the premolar and incisor teeth are un- 
known. The section II, approximates nearer the genus Conoryctes than 
sect. I. 
Mesodonta. 
Hyopsodus eemoinianus, sp. nov. 
This Mesodont is distinguished from the known species of the genus by 
its superior size, and the fully developed heel of the inferior third molar. 
The anterior inner cusps of the inferior molars are absolutely simple, and 
the same teeth have a weak external and no internal cingulum. The cusps 
are elevated and the enamel smooth. 
The species of this genus known to me by their mandibles are four, and 
these differ chiefly in size. Their characters are as follows : 
Length of true molars M. .0165 ; last molar elongate II. lemoinianus. 
Length of true molars M. .0140 ; last molar longer than second 
II. paulus. 149 
1881.j 
[Cope* 
Size as last; last molar shorter than second H. miticulus. 
Length of true molars M. .0115 ; last molar elongate H. vicarius. 
IT. lemoinianus and H. miticulus have not been found out of the localities 
where they were discovered, while the other two species are distributed 
through most of the Eocene horizons, and have* been found in many 
localities. Of the H. lemoinianus Mr. Wortman found nine more or less 
fragmentary mandibles. 
Dedicated to my friend, Dr. Victor Lemoine of Reims, well-known for 
his brilliant discoveries in the vertebrate paleontology of the Lower Eo- 
cene beds near that city. 
Hyopsodus faulus Leidy. 
Thirty-eight more or less broken mandibular rami. 
Hyopsodus vicakius Cope. 
Eleven mandibular rami. A few specimens are intermediate betw-een 
this species and the last in dimensions, the inferior true molars measuring 
M. .0120 and .0125 in length. 
Pantolestes chacensis Cope. 
Four mandibular rami. This species has the fourth premolar more 
robust and less trenchant than in P. secans, and shorter than the last true 
molar. In P. secans it is longer than the last true molar. 
PANTOLESTES METSIACUS Sp. nOV. 
A small species of the size of the P. longicaudus, and distinguished by 
several peculiarities of dentition. The two cusps composing the anterior 
internal lobe of the molars are quite distinct hut appressed. Each one is 
connected with the external anterior lobe by a transverse crest as is seen 
in Estlionyx, and these enclose between them a fossa. This fossa is closed 
internally by the appression of the anterior inner cusps. The fourth pre- 
molar is not so large as in P. secans, but resembles in proportions that of 
P. chacensis. It differs from that of P. longicaudus in its very short heel 
and its large anterior basal tubercle. The latter is double, consisting of 
two small cusps, one within and anterior to the other. The posterior heel 
is distinct on both sides of the ridge that marks the median line. The 
posterior external lobe is V-shaped, and the posterior inner is a small cone. 
Between the two is a minute median tubercle. The posterior tubercles are 
not so elevated as in the species of Hyopsodus. A weak external cingulum ; 
enamel smooth. 
Length P-m. IV, with M. I, and II; (No. 1) 0140 
“ P-m. IV 0048 
“ M. II 0043 
Measurements. 
M. Cope.] 
150 
fDec. 16, 
Measurements. 
M. 
Width M. II 0040 
Length M. Ill; (No. 2) 0050 
Width “ 0080 
Depth ramus at.P-m. IV ; (No. 1) 0060 
“ “ M. Ill; (No. 2) 0070 
Portions of four mandibles preserved. No. 2 is a little smaller than 
No. 1, and No. 4 is a little larger than No. 1. 
The species of Pantolestes may be distinguished as follows : 
a. Fourth premolar trenchant everywhere, longer than second molar. 
Length of true molars M. .0150 ; second molar with but one anterior inner 
cusp P. seeans. 
aa.. Fourth premolar with blunt heel, not longer than second molar. 
Length of true molars .0160 ; all with double cusps P. chacensis. 
Length of true molars .0140 ; fourth premolar with minute anterior cusp, 
and long heel P. longicaudus. 
Length of true molars .0180 ; fourth premolar with double anterior cusp, 
and short heel; molars with double cusps P. metsiaeus. 
Length of true molars .0105 ; fourth premolar small, .0035, without an- 
terior cusps, and with two ridges on heel; true molars with double an- 
terior inner cusps P. nuptus. 
Pantoeestes nuptus, sp. nov. 
This is the last species of the genus, and is represented by a portion of a 
right mandibular ramus which supports three molars from the fourth to 
the sixth inclusive. Besides its small size, this species is distinguished by 
the relatively small dimensions of the fourth premolar, which is shorter 
than the first true molar instead of longer, as in all the other species. The 
well developed basin of its heel, which is bounded by a ridge on each side, 
distinguishes it at once also from P. seeans, and is more distinct than in P. 
chacensis ; from the latter and P. metsiaeus the entire absence of anterior 
basal lobes separates it. The well developed pair of anterior inner tuber- 
cles of the true molars shows that it cannot be an abnormal Hyopsodus vica- 
rius, with which it agrees in size. The first anterior tubercle is more widely 
separated from the second anterior than in any of the species of the genus, 
and is quite as in species of Pelyeodus. It is smaller than the second ante- 
rior inner, which equals in size the anterior outer. The heel is wide, en- 
closing a basin, which is bounded externally by an angular ridge. Its 
posterior inner angle supports a cusp, which is separated by a deep notch 
from the anterior inner cusp. External to it on the posterior border of 
the crown is a small tubercle. No basal cingula. 
Length of three molars 010 
Measurements. 
M. 
Diameters of M. i 
anteroposterior 004 
transverse 008 
Depth of ramus at P-m. IV 007 
Basin of the Big-Horn ; J. L. Wortman. 1881.1 
151 
[Cope. 
Pelycodus angulatus Cope. 
The species of this genus are, in the present state of our knowledge, best 
distinguished by their size. 
Length of true molars on base M. .024 ; P. pelvidens* 
“ “ “ “ M. .019; P. jarrovii. 
“ “ “ “ M. .017; P. tutus. 
“ “ “ “ M. .015 ; P. frugivorus. 
“ “ “ “ M. .012; P. angulatus. 
Remains of species of this genus are very common in the Wind River 
bad lands ; they were originally found in the Wasatch beds of New 
Mexico, and have not yet been announced from the Bridger formation. 
The P. angulatus, heretofore only known from New Mexico, is rep- 
resented in the Big-Horn collection by five mandibular rami, and a por- 
tion of a maxillary bone with teeth. 
Pelycodus frugivorus Cope. 
Two mandibles and seven separate rami represent this Mesodont. 
Pelycodus tutus Cope. 
Four rami display the typical length of the true molars, M. .017. Three 
are smaller, having the molars .016 in length, w hile one gives .018 for the 
same teeth. Other portions of the skeleton will be necessary to deter- 
mine exactly the specific position of these specimens. 
Cynodontomys latidens, gen. et sp. nov. 
Char. gen. Derived from mandibular rami. Dental formula I. ? 0 ; C. 
1 ; P-m. 2 ; M. 3. The premolars are counted as two, on the supposition 
that the anterior one is two-rooted ; should it prove to he one-rooted, then 
the number will be three. The canines are very large and close to the 
symphysis, so that there do not appear to have been any incisors. The 
true molars have the frequently occuring three tubercles in front and a 
heel behind ; but the arrangement is peculiar in that the three tubercles 
are but little more elevated than the borders of the heel, and occupy a 
small part of the crown. The last molar is lost from both jaws, but the 
space for it is about as large as that occupied by the penultimate. The 
fourth premolar lias but two anterior cusps, and these are more elevated 
than those of the true molars, and the heel is narroiver. The mandibular 
rami are not coossified. 
The dental characters of this genus resemble considerably those of 
Anaptomorphus and Necrolemur, but the large size of the inferior canine 
tooth distinguishes it from both. The double anterior cusps of the fourth 
premolar equally distinguish it from them. 
Char. Specif. The inferior true molars are suhquadrate in horizontal 
outline, somewhat narrowed anteriorly. The concave heel is the larger 
part of the crown ; it is only elevated into a low cusp at the posterior 
external angle. The anterior cusps are conic, and are in contact at the 
Prosimias. 
* Lipodectes pelvidens Cope, Amev. Naturalist, Dec., 1881, p. 1019. Cope.] 
152 
I Dec. 16, 
base. The external and posterior internal are of about the same size ; 
the anterior inner is smallfer and does not project so far inwards as the 
posterior. The fourth premolar has the posterior border of its heel ser- 
rate. The anterior cusps are elevated and moderately acute ; the internal 
is a little less elevated than the external, and is separated from it by a 
deep notch. The alveoli for the anterior premolar are so close together, 
as to render it probable that they belong to but one tooth. They are 
placed somewhat obliquely to the long axis of the jaw. There is no 
diastema. The section of the base of the crown of the canine is a regular 
oval, the long diameter coinciding with the vertical diameter of the 
ramus. 
The ramus is rather slender, but is shortened anteriorly. The bound- 
aries of the masseteric fossa are well marked, the anterior ridge descend- 
ing to below the middle line of the ramus. The mental foramen is large 
and is situated below the contact of the two premolars. The inferior edge 
of the ramus is rather thick. 
Measurements. 
M. 
Length of dental series including canine 0240 
“ pre molars 0062 
“ molars 0114 
Long diameter base canine 0036 
anteroposterior 0038 
transverse 0026 
Diameters P-m. IY 
“ “ M. II. 
anteroposterior 0042 
transverse 0038 
Depth of ramus at P-m. 1 0060 
“ “ “ M. Ill 0068 
Anaptomorphus homunculus Cope, American Naturalist, 1882, Jan. 
(Dec. 30th, 1881), p. 73. 
The genus Anaptomorphus was characterized by me in 1872,* from a 
mandibular ramus which exhibited the alveoli of all the teeth, three of 
them occupied by the teeth ; viz. : the P-m. iv, and the M. i and M. ii. 
From the specimen the inferior dental formula was ascertained to be I. 2 ; 
C. 1 ; P-m. 2 ; M. 3. The Big-Horn collection contains a nearly entire 
cranium of what is probably a species of the same genus. From it the 
superior dentition, exclusive of the incisors, is determined to be : C. 1 ; 
P-m. 2 ; M. 3. The premaxillary bones are mostly broken off, but a part 
of the alveolus of the external incisor of one side remains. 
The indications are that the external incisor was a small tooth, not 
exceeding the canine in size ; and it was situated close to the latter. The 
canine is also small, and its simple crown is not more prominent than those 
of the premolars. The latter are separated from it by a very short diastema. 
The long diameter of their crowns is transverse to the long axis of the 
* Proceedings American Philosophical Society, 1872, p.554. Paleontological 
Bulletin, No. 8, p. 1, Oct. 12, 1872. 1881.] 
153 
[Cope. 
jaw ; and each one consists of a larger external, and smaller internal cusp. 
The true molars are also wider than long, and support two external and 
only one internal cusps. 
The orbits are large and are entirely enclosed behind. The frontal bone 
does not send inwards to the alisphenoid a lamina to separate the orbit 
from the temporal fossa, as is seen in Tarsius. There is no sagittal crest, 
hut the temporal ridges are distinct. The occipital region protrudes beyond 
the foramen magnum, or at least beyond the paroccipital process, which is 
preserved, the condyles being lost. The otic bulla is large, extending 
anteriorly to the glenoid cavity. The pterygoid fossa is large, the external 
pterygoid ala being well developed, and extending well upon the extero- 
anterior side of the bulla, as in Tarsius. As in that genus, the foramen 
ovale is situated on the external side of the bulla, just above the base of 
the external pterygoid ala. The carotid foramen, as I suppose it to be, is 
situated at the apex of the bulla. The lachrymal foramen is situated 
anterior to, and outside of the orbit as in Lemuridcc generally. 
The cast of the anterior part of the left cerebral hemisphere is exposed. 
This projects as far anteriorly as the middle of the orbits, leaving but 
little room for the olfactory lobes. The relations of the latter as well as 
of other parts of the brain will be examined at a future time. The part 
exposed does not display fissures, and gentle undulations represent con- 
volutions. 
The characters of this genus now known, warrant us in thinking it one 
of the most interesting of Eocene Mammalia. Two special characters 
confirm the reference to the Lemdridoe which its physiognomy suggests. 
These are, the external position of the lachrymal foramen, and the un- 
ossified symphysis mandibuli. Among Lemuridcc, its dental formula agrees 
only with the Indrisinos, which have, like Anaptomorphus, two premolars 
in each jaw. But no known Lemuridce possess interior lobes and cusps of 
all the premolars, so that in this respect, as in tjie number of its teeth, 
this genus resembles the higher monkeys, the Simiidce and Hominida,,* 
more than any existing member of the family. Of these two groups the 
resemblance is to the Hominidw in the small size of the canine teeth. It 
has, however, a number of resemblances to Tarsius which is perhaps its 
nearest ally among the lemurs, although that genus has three premolars. 
One of these points is the anterior extension of the otic bullae, which is 
extensively overrun by the external pterygoid ala. A consequence ot 
this arrangement is the external position of the foramen ovale, just as is 
seen in Tarsius. Another point is the probably inferior position of the 
foramen ovale. Though this part is broken away in the cranium of Anapto- 
morphus homunculus, the paroccipital process is preserved, and has the 
* In an early description of Anaptomorphus, Proc. Amer. Philos. Soc., 1873, the 
types make me say “this genus * * might he referred decidedly to the Le- 
muridce, were it not tor the unossified symphysis.” It is scarcely necessary to 
state that Simiidce should be read in place of Lemuridce. Cope.] 
154 
[Dec. 16, 
position seen in Tarsius, as distinguished from the Indrisince, Lemurince, 
Galagince, etc. In this it also resembles the true Quadrumana. 
When we remember that the lower Quadrumana, the JTapalidce and 
the Cebidce, have three premolar teeth, the resemblance to the higher mem- 
bers of that order is more evident. The brain and its hemispheres are not 
at all smaller than those of the Tarsius, or of the typical lemurs of the 
present period. This is important in view of the very small brains of the 
flesh-eating and ungulate Mammalia of the Eocene period so far as yet 
known. In conclusion, there is no doubt, but that the genus Anapto- 
morphus is the most simian lemur yet discovered, and probably represents 
the family from which the true monkeys and men were derived. Its dis- 
covery is an important addition to our knowledge of the pliylogeny of 
man. 
Char, specif. The specimen is distorted by pressure, but its form is 
normally nearly round, when viewed from above or below. The extremity 
of the muzzle is broken away, but the alveolus of the external incisor in- 
dicates that it is short, and not prolonged as in Tarsius spectrum. The 
mandibular ramus, already described, proves the same thing. The orbits 
are large, but not so much so as in Tarsius spectrum ; their long diameter 
equals the width of the jaws at the last superior molar teeth inclusive. 
The supra-orbital borders project a little above the level of the frontal 
bone, which is concave between their median and anterior parts. The 
cranium is wide at the postorbital region, in great contrast to its form in 
the Adapidce, resembling the Necrolemur antiquus Filli. in this respect. 
The postfrontal processes are wide at the basal portion, and flat. From 
their posterior border the temporal ridges take their origin. These converge 
posteriorly and probably unite near the lambdoidal suture, but this part 
of the skull is injured. The anterior lobes of the cerebral hemispheres 
are indicated externally by a low boss on each frontal bone. 
The paroccipital process is short and wide at the base, and it is directed 
downwards ancj forwards. The alisphenoid descends so as to form a strong 
wall on the anterior external side of the otic bulla. This is also the case 
in Tarsius spectrum, but in the extinct species the descending ala is more 
robust, and has a thickened margin. On the latter the external pterygoid 
ala rests by smooth contact of its thickened superior edge. This ala is 
twice as prominent as the internal pterygoid ala. The posterior nareal 
opening is not wide, and its anterior border is parallel with the posterior 
border of the last superior molar teeth. The palate is wide, and its dental 
borders form a regular arcade as in man, being quite different from the 
form usual in monkeys and lemurs, including Tarsius. Perhaps the form 
is most like that of Microrhynchus laniger. The proximal parts of the 
malar bone are prominent, and overhang the maxillary border, as in 
Tarsius. 
The foramina ovale and lachrymale are rather large. There are two 
infraorbital canals, tying beside each other, and issuing by two foramina 
externa. The external appearance justified this conclusion, but the fact 1881.] 
155 
[Cope. 
was demonstrated when I accidently broke away the anterior border of one 
of the orbits. This displayed the two canals filled with matrix their entire 
length. The anterior foramen externum is anterior to and above the 
posterior, and both are above the first (third) premolar tooth. The 
lachrymal foramen is above the space between that tooth and the canine. 
The crown of the canine tooth is a cone with a very oblique base, and a 
convex anterior face. The base rises behind, and the posterior face has on 
the median line a low angular edge. The internal cone of the third (first) 
premolar is not so prominent as that of the second, though large. The 
external cusps of both premolars rise directly from the external base. They 
are flattened cones, with anterior and posterior cutting edges. The 
crowns are a little contracted at the middle, so as to he narrower than the 
inner lobe of the tooth, which is narrower than the external portion. Both 
premolars have delicate anterior, posterior and external cingula. The ex- 
ternal cusps of the true molars rise directly from the external base, and 
like those of the premolars, have a regularly lenticular section. At the 
internal base of each one is a small intermediate tubercle, which is con- 
nected by an angular ridge with the single internal cusps. There are 
delicate anterior, posterior, and external cingula, hut no internal. The 
posterior cingulum shows a trace of enlargement at its inner part, which 
is well marked on the second molar, but it is not as prominent as in many 
Creodont genera. The posterior external cusp of the last true molar is 
reduced in size. Taking the molars together, the first true molar is the 
largest, and they diminish in size both anteriorly and posteriorly. The 
third true molar is a little smaller than the first (third) premolar. Enamel 
smooth. 
M. 
Length of cranium to occipital prominence above par- 
occipital process, and minus premaxillary bone.. !0280 
Total width at posterior border of orbit, below 0240 
Length of palate from front of canine tootji 0116 
Width of palate and peunltimate molars 0125 
Length of superior molar series 0095 
“ “ true molars 0060 
Measurements. 
Diameters of crown of canine 
anteroposterior 0018 
vertical 0018 
Diameters crown of P-m. iii, 
anteroposterior 0020 
transverse 0026 
anteroposterior 0020 
transverse 0035 
Diameters crown of P-m. iv, 
anteroposterior 0082 
transverse 0040 
Diameters.M. ii, 
Diameters M. iii, 
anteroposterior 0016 
transverse 0028 
Diameters of orbit 
anteroposterior 0110 
vertical (? depressed) 0078 
Interorbital width (least) 0050 156 
Cope.] 
[Dec. 1«, 
The Anaptomorplius homunculus was nocturnal in its habits, and its food 
was like that of the smaller lemurs of Madagascar and the Malaysian 
islands. Its size is a little less than that of the Tarsius spectrum. The 
typical specimen was found by Mr. J. L. Wortman in a calcareous nodule 
in the Wasatch formation of the Big-Horn basin, Wyoming Territory. 
Creodonta. 
Shortly after the publication of my arrangement of the Creodonta in 
1880*, I obtained a good deal of additional material, which enabled me to 
improve it in several respects. A number of genera have been added, and 
the characters which distinguish the Miacidce and Oxycenidce have been 
more fully brought out. The Miacidce differ from all other families in 
having the fourth superior premolar sectorial as in the true Carnivora, 
while the true molars are tubercular. In Oxycena, the fourth superior pre- 
molar displays no indication of sectorial structure, the first true molar 
assuming that character. In Stypolophus and allies, the second superior 
true molar is more or less sectorial, and the first true molar and even the 
fourth premolar in some of the genera, develop something of the same 
character. But there is every gradation between the triangular Bidelphys- 
like, and the sub-sectorial Pterodon-like forms of the superior molars, in 
this group of genera. 
The glenoid cavity of the squamosal bone presents differences in the 
various genera of this sub-order. In Arctocyonidce (fide De Blainville), 
Oxycenidce, and Mexonychidce, it is bounded by a transverse crest anteriorly, 
as well as by the postglenoid posteriorly, while in the Leptictidce it is plane 
and open anteriorly. In Amblyctonidce its condition is unknown. In 
existing Carnivora this character is not very constant as a family defini- 
tion ; it is,best marked in the Felidce, and least marked in the Canidce. 
Nevertheless there is a group of genera allied to the Oxycenidce, which are 
very marsupial in character, which have been called the Leptictidce, and 
which differ so far as known from Oxycena in the absence of the preglenoid 
crest. I suspect that these forms constitute a family by themselves, and 
for the present, until our knowledge of them is fuller, I define it by this 
character. The definitions of the families will then be as follows : 
I. Ankle-joint plane transversely, or nearly so. 
True molars above and below, tubercular ; last superior not transverse.... 
Arctocyonidce. 
Superior true molars, tubercular ; last superior premolar sectorial ; first 
inferior molar “tubercular sectorial” Miacidce. 
Superior last molar transverse ; inferior molars tubercular-sectorial or with 
reduced anterior cusp ; no preglenoid crest Leptictidce. 
Last superior molar trenchant, transverse ; first superior true molar sec- 
torial ; inferior true molars tubercular-sectorial ; a preglenoid crest... 
Oxycenidce. 
♦Proceedings Amer. Philos. Society, p. 76. 157 
1881.] 
[Cope. 
Last superior molar longitudinal ; inferior true molars without developed 
sectorial blade AmblyctonidcB. 
II. Ankle-joint tongued and grooved, or trochlear. 
Molar teeth in both jaws consisting of conic tubercles and heels ; none 
sectorial; a preglenoid crest Mesonychida. 
I now give the characters of the genera. All these are derived from 
examination of typical specimens. The opportunity of doing this 1 owe 
to the kindness of Messrs. Leidy, Gervais, Gaudry, Filhol, and Lemoine. 
Akctocyonidas. 
Premolars, £ ; the first inferior one-rooted ; the last inferior well developed ; 
Arctocyon Blv. 
Premolars below, 4, the first two-rooted, the last true molar much reduced ; 
(fide Lemoine) Ryodectea Cope. 
Premolars below, 3, first two-rooted ; true molars normal 
Reteroborus Cope. 
Miacid^e. 
Inferior tubercular molars two, premolars four Miacis Cope. 
Inferior tubercular molars one, premolars four Didymictis Cope. 
Leptictida?. 
I. Superior molars sub-equilateral, without cutting heel posteriorly. 
a. Fourth inferior true molar like the true molars, with three anterior 
* 
cusps. 
Third superior premolar with internal cusp ; anterior cusp of in- 
ferior molars small, median. 
Third premolar with one external and one internal cusps.Mesodeetes Cope. 
Third premolar with two external and one internal cusps... .Ictops Leidy. 
/9/3. Third superior premolar without internal cusps ; anterior cusps of 
inferior molars present. 
Cusps of superior molars marginal; two superior incisors ; Leptictis Leidy. 
Cusps of superior molars median in position ; anterior cusp of inferior 
molars well developed Peratherium Aym. 
Anterior cusps of inferior molars wanting. 
Fourth inferior premolar like true molars Diacodon Cope. 
aa. Fourth inferior premolar different from true molars in a simpler 
constitution. 
Last inferior molar tubercular ; cusps of other true molars well developed; 
three inferior premolars Lipodectes Cope. 
Inferior true molars alike, with anterior inner cusps little developed ; three 
premolars (?) Triisodon Cope. 
Inferior true molars alike, with cusps well developed ; four premolars. ... 
Delta therivm Cope. Cope.] 
158 
[Dec. l(>, 
II. One or more superior molars, with the external heel produced into 
a blade. 
a, Molars 4—3 ; three last inferior tubercular sectorial. 
Premolars robust, conic Quercitherium Filh. 
Premolars compressed ; the fourth superior with a conic cusp and heel 
externally Stypolophus Cope. 
Premolars compressed ; fourth superior with a simple blade externally... 
Proviverra Riitim. 
OxY^EKimE. 
I. Inferior molars without internal tubercles. 
Molars, f f ; three sectorials in the lower jaw Pterodon Blv. 
II. Inferior molars with internal cusps. 
a. Posterior heel of one or more superior molars elongate and trench- 
ant. 
Last inferior molar truly sectorial, without internal tubercle ; second, 
tubercular-sectorial Protopsalis Cope. 
Molars, | § ; two last inferior molars tubercular-sectorial... Oxycena Cope. 
Amblyctonid^e. 
Fourth, inferior premolar with a broad heel supporting tubercles; an 
anterior and no internal tubercles Amblyctonus Cope. 
Inferior molars with tubercular heel, an anterior and an internal tubercle. 
' Periptychus Cope. 
Dental formula below, 3, 1, 3, 3. Fourth inferior premolar with a cutting 
edge on the heel; both internal and anterior tubercles 
Palceonycth Blv. 
Mesonychid^e. 
a. Inferior molars seven ; 
Cones of inferior and superior molars simple Mesonyx. 
Cones of last two inferior molars with lateral cusps Dissacus. 
aa. Inferior molars ? six. 
Internal lobes of penultimate superior molar v-shaped Sarcothraustes. 
aa. Inferior molars five. 
Inferior molars with strong anterior lobe Patriofelis * 
Miacis canavus Cope. 
Bulletin U. S. Geol. Survey, Terrs., 1881, p. 189. One mandible. 
Miacis brevirostris Cope, loc. cit. p. 190. 
Parts of four mandibles. 
Didymictis dawkinsianus Cope, 1. c., p. 191. 
Six mandibular rami more or less complete. 
Individuals of the genus Didymictis are abundant in the Wasatch beds 
* Of uncertain reference to this family. 1881.] 
159 
[Cope. 
of the Big-Horn, and a good «iany of them do not coincide well in 
characters with the species already described. I define them as follows, 
premising that with other parts of the skeleton some changes may be found 
to be necessary. The large D. altidens was not obtained by Mr. Wortman 
in the Big-Horn country. 
I. Inferior tubercular molar oval in outline, with a heel. 
Length true molars .010 ; last three premolars .0135 ; last molar narrow.. 
D. dawkinsianus. 
Length true molars .016—.018; last three premolars .028—.030; last 
molar narrow D. leptomylus. 
Length true molars .019—.020; last three premolars .036; last molar 
elongate D. protenus. 
Length true molars .025 ; last three premolars .035 ; last molar short... 
D. altidens. 
II. Inferior tubercular molar short, subquadrate in outline. 
Length true molars .011 ; depth of ramus at sectorial .010 
D. massetericus. 
Length true molars .018 ; depth of ramus at sectorial .017 D. curtidens. 
Didymictis leptomylus Cope. 
American Naturalist, 1880, p. 908. 
The specimens which I refer at present to this species belong to two 
varieties, which may perhaps be specifically distinct; but this cannot be 
demonstrated at present. They differ in dimensions only. Thus the true 
molars of the type, which comes from the Big-Horn beds, measure 
M. .016 in length. Five specimens from the Big-Horn basin agree in hav- 
ing this dimension .018. The entire inferior molar series is only a little 
shorter than that of the smaller variety of the D. protenus from New 
Mexico (See my report to Capt. Wheeler, plate xxxix). 
Didymictus protenus Cope. 
Jaws more or less complete, of six individuals, are referable to this 
species. They agree closely in measurements and belong to the larger 
variety of the species figured on plate xxxix of the report to Capt. 
Wheeler. 
Didymictis massetericus, sp. nov. 
This species is intermediate in size between the D. leptomylus and the 
_D. dwwkinsianus, and is characterized by the peculiar form of its tubercular 
molar, and the deeply excavated masseteric fossa. It appears to have been 
a rare species, as only one mandibular ramus was found by Mr. Wortman. 
This is broken off in front of the fourth premolar, and supports the last true 
molar teeth. 
The tubercular molar is subquadrate in form, and consists of three low 
tubercles in front, and a wide heel behind, which has an elevated posterior 
border. The tubercular-sectorial has a short and narrow heel. Its anterior 
cusps are not very acute, and the two internal are equal, and a good deal Cope.] 
160 
[Dec. 1«, 
shorter than the external. The fourth premolar is relatively shorter than 
in any other species of the genus, and the posterior marginal lobe is a mere 
thickening of the edge of the heel. There is a low anterior basal tubercle. 
The enamel is smooth. 
The ramus is compressed and not deep. The angle is prominent, and is 
not inflected ; it does not extend so far posteriorly as the posterior border 
of the condyle. The inferior border of the masseteric fossa is an angular 
line, without abrupt excavation, but the face of the fossa descends rapidly. 
The anterior border of the fossa is abrupt and is formed by the usual sub- 
vertical ridge. 
Length between P-m. IV, and condyle inclusive 0520 
“ of posterior three molars 0170 
“ of tubercular-sectorial 0070 
Elevation of “ “ 0070 
Depth of ramus at sectorial 0100 
Measurements. 
M. 
Didymictis curtidens, sp. nov. 
As in the case of the D. massetericus the present species is represented 
by a single fragmentary mandibular ramus. This supports a sectorial tooth 
of the size and form of that of the D. protenus, and is thus much larger 
than that of the species just named. This tooth is placed nearer to the 
base of the coronoid process than is seen in any other species, and only 
leaves space for a short tubercular tooth. This is lost from the specimen, 
but the alveolus shows pretty clearly its dimensions. The base of the 
fourth premolar remains, and it is evident that this tooth was like that 
of D. protenus in form and proportions. The base of the posterior marginal 
lobe is present. The ramus is deeper and larger than in the D. massetericus. 
Length of bases of last three molars 0285 
“ fourth premolar 0120 
“ “ of sectorial on base 012 
Width “ in front 008 
Depth of ramus at sectorial 017 
Measurements. 
M. 
Ictops bicuspis Cope. Bull. U. S. Geolog. Surv., Terrs. 1881, p. 192. 
This mammal was founded on a skull from the Wind River region. 
It is now represented by a mandibular ramus. The form of the fourth 
premolar being unknown, its reference to this species is provisional only. 
It may be remotely allied to Stypolophus, but the anterior inner cusp of the 
molars is small and does not reach the inner side of the crown, and the an- 
terior external cusp is but little larger than the second anterior inner. The 
two cusps last named stand opposite to each other, and their apices are only 
separated from each other by an open notch. They, with the first anterior 
inner (here median), form a transverse narrow triangle. The posterior 
part of the crown is rather large and, though lower than the anterior part, 161 
1881.] 
[Cope. 
is absolutely quite elevated above the alveolar border. Its summit presents 
a V externally, and there is a small posterior median angle. In the last 
true molar this angle is a little more prominent than in the others, and 
rises into a cusp. The external bases of the crowns are protuberant, but 
there are no cingula. Enamel smooth. 
The ramus is rather compressed, and the masseteric fossa is well marked, 
and is bounded anteriorly by a prominent rib. 
Length of true molars 0100 
Measurements. 
M. 
Diameters M. Ill 
anteroposterior .0085 
vertical 0085 
transverse 0080 
Diameters M. I 
anteroposterior 0085 
transverse *.... .0028 
This species is smaller in all dimensions than I. didelphoides, and the 
crowns of the molar teeth are shorter and more elevated than in that 
species. 
Depth of ramus at M. II 0070 
Deltatherium absarokas Cope. American Naturalist, 1881, p. 669. 
A small species, represented by an imperfect cranium and lower jaw 
with nearly complete dentition. 
Stypolophus aculeatus Cope. 
Several fragmentary mandibles nearly coincide in measurements with 
this species. The molars are .0240 in length, and the ramus is .0140 in 
depth. The only difference in the measurements is that the true molars 
measure .0250 in <8. aculeatus. The latter is, however, a species of the 
Bridger epoch, so that further comparison will be necessary before identi- 
fication is made. 
Stypolophus sp. nov. 
Stypolophus strenuus Cope. Bulletin U. S. Geol. Survey, vi, 192 ; not 
of Report Capt. Wheeler, vol. iv, pt. ii. 
The greater part of the skeleton, with skull and dentition of this species, 
were brought from the Big-Horn by Mr. Wortman. A part of a mandible 
of a second individual was also found. The species is, however, primarily 
based on a specimen from the Wind river. This is represented by a right 
mandibular ramus which supports all the molar teeth, and displays the 
alveolus of the canine, and lacks all posterior to the coronoid process ; 
also by a portion of the frontal bone, two vertebrae, fragments of scapula, 
humerus, ulna, radius, ilium, and tibia, and the greater part of both tarsi. 
They represent a species larger than the Virginian opossum, and inter- 
mediate between the 8. brevicalcaratus and S. strenuus in proportions. It 
has not the rudimental heels of the molars of the former species, nor the 
robustness of the latter. 
The inferior outline of the mandible is gently curved from the canine Cope.] 
162 
[Dec. 16, 
to below the last molar. The anterior border of the masseteric fossa is well 
marked, but not the inferior border. The ramus is compressed and deep. 
The canines have stout roots and narrow curved crowns. The first premo- 
lar is separated by a short space from the canine and by a longer one from 
the second premolar. It has either a single compressed root or two roots 
confluent Avithin the alveolus. The crown is truncated obliquely behind. 
The second premolar is two-rooted and the crown is elevated anteriorly 
and depressed posteriorly. The third premolar is more symmetrical, but 
the heel is produced. It is narrow and keeled medially. The fourth pre- 
molar is abruptly larger than the third. Its crown is simple, except a low 
tubercle at the anterior base and a short trenchant heel at the posterior 
base. Of the three tubercular-sectorials the first is the smaller. The heels 
of all three are rather narrowed and elongate. Their margin is raised all 
round, inclosing a basin ; a notch in the external margin cuts its anterior 
part into a tubercle. The two internal tubercles are rather obtuse, and are 
considerably shorter than the external cusp. 
Length from canine to end of last molar 060 
“ first true molar 007 
“ “ second premolar 015 
“ of base of fourth premolar .009 
Elevation of fourth premolar 007 
Length of base of second true molar 007 
“ heel “ “ “ 006 
Elevation of second true molar 009 
Depth of ramus at third premolar 015 
Length of superior canine 028 
“ crown of superior canine with enamel 012 
Measurements. 
M. 
A portion of the frontal bone shows weak anterior temporal ridges 
uniting early into a sagittal crest, which is low as far as preserved. The 
parietal bones overlap the frontal as far forwards as the temporal ridges. 
Anterior to the latter the front is concave in transverse section. Viewed 
from below, the spaces for the olfactory lobes are large and entirely an- 
terior to those which received the anterior lobes of the hemispheres.; each 
one is about as wide as long. In the small part of the cerebral chamber 
wall left, there is no indication of convolutions, which would be visible in 
a gyrencephalous brain ; two air-chambers in front of each olfactory lobe. 
The base of the transverse process of the atlas is perforated from be- 
hind to the middle of its inferior side ; from the latter opening a foramen 
penetrates directly into the neural canal. A posterior dorsal vertebra has 
the centrum longer than wide and much depressed. Its inferior face is 
regularly convex in section. The proximal end of the scapula shows that 
its inner border is much thickened, and that the spine arises abruptly and 
near to the glenoid cavity. There appears to have been scarcely any cora- 
coid ; the surface adjoining it is, however, injured. The humerus lacks 163 
1881.] 
[Cope. 
the proximal portion and the inner half of the condyles with the epi- 
condyles. The deltoid crest is not very prominent, so that the shatt is 
rather slender. The external distal marginal crest is thin, and is continued 
well up on the shaft. The external part of the condyle displays no inter- 
trochlear ridge. Olecranar and coronoid fossae well marked. The olecranon 
is robust and deep, and is truncate posteriorly and below. The head of 
the radius is a regular ti'ansverse stout oval. 
A fragment of the ilium from near the acetabulum displays a prominent 
“anterior inferior spine.” The best preserved tarsus includes calcaneum, 
astragalus, cuboid, and navicular bones. The tibial face of the astragalus 
is strongly convex antero-posteriorly and slightly concave transversely. 
The head is prolonged some distance beyond the distal extremity of the 
calcaneum, and presents a convex internal border and a concave external 
one. Its long axis is parallel to that of the tibial portion, but is not in the 
same axis, owing to its lateral position. The external face of the trochlear 
portion is vertical, and is interrupted by a deep fossa behind. The internal 
face is very oblique, and becomes the superior face of the head. The 
posterior face of the trochlea is grooved with a wide and shallow grove, 
which just reaches the superior face, terminating on the external side. 
The superior face is not grooved, but is shallowly concave in transverse 
section. The head is a transverse oval, and is convex ; it has a small facet 
for the cuboid on the outer side. 
The heel of the calcaneum is large and expands distally, so as to be as 
wide as deep. The convex astragalar facet is very oblique to the long 
axis of the calcaneum ; the sustentaculum is rather small. Below the 
latter is a narrow tuberosity looking downwards and forwards. On the 
external side, close to the cuboid facet, is a depressed crest. The cuboid 
facet is as deep as wide. The cuboid bone is a little longer than wide 
proximally, and narrows distally. It has a narrow astragaline facet and 
a deep fossa below proximally. The hook inclosing the groove for the 
tendon of the flexor muscle is prominent. The navicular is rather small, 
and has three inferior facets, which diminish in size outwards. It has a 
strong posterior knob-like process, with a narrow neck. 
When the tarsal bones are in position, and the tibia stands vertically on 
the astralagus, the cuboid bone is turned interiorly. This indicates that this 
species walked on thexmter edge of the hinder foot. 
Broken metapodial bones are slender and straight. The proximal end 
of a metacarpal does not display the interlocking lateral articulation seen 
in Protopsalis. Two phalanges are depressed in form. 
Measurements. 
anteroposterior 0145 
vertical 0075 
transverse 0115 
M. 
Diameters of a dorsal centrum 
Diameters of glenoid cavity scapula 
anteroposterior 0145 
transverse 0090 Cope.] 
164 
[Dec. 16, 
Measurements. 
M. 
Depth of olecranon 0110 
Width of head of radius 0110 
“ neck of ilium anteroposteriorly 0120 
Diameter of shaft of tibia at middle 0085 
anteroposterior 0180 
greatest 
Diameters of astragalus 
transverse. 
of trochlea 0140 
of head 0100 
Length of head 0070 
“ calcaneum t 0300 
Width of calcaneum at sustentaculum 0140 
“ cuboid facet 0066 
Length of cuboid 0120 
distal 0070 
proximal 0075 
Diameters 
anteroposterior 
transverse proximal .0098 
vertical 
with tuberosity ... .0100 
without tuberosity 0070 
Diameters of navicular 
transverse 
anteroposterior 
As already remarked, it is probable that the semigrooved trochlea of the 
astragalus of this species is an indication that the genus Prototomus must 
be retained as distinct from Stypolophus, to which the present species proba- 
bly truly belongs. 
The specimen described, together with the mandibular ramus of another 
supporting the last two molar teeth, were found in the bad lands of Wind 
river, Wyoming, by J. L. Wortman. Dedicated to Frances Emily White 
M. D., of Philadelphia. 
FORCIPATA Cope. 
Report Yert. Foss., New Mexico, 1874, p. 12. Report Capt. G. M. 
Wheeler, U. S. G. G., Expl. Surv. W. of 100th Mer. iv, ii, p. 105, 1877. 
This formidable animal was abundant in Northern Wyoming, during the 
Wasatch epoch. At least ten individuals are represented in the collection. 
The following are the dimensions of the mandibles of the five best pre- 
served. 
1 1 2 
8 4 
5 
Length of dental series 
.103 ? 
.100.100 
.107 
“ premolar “ 
.042 .045 
.044.051 
.054 
Depth of ramus at M. Ill 
.042 .039 
.037.042 
.047 
The measurement .035 for the length of the premolars given in my 
report to Capt. Wheeler, loc. cit., refers to the anterior three teeth, which 
were originally supposed to be the only premolars. 1881.] 
165 
[Cope. 
The claws of this species are moderately compressed, and they termi- 
nate abruptly and obtusely. The extremity is deeply fissured, and each 
of the two apices is rugose. 
Mesonyx ossifragus Cope, American Naturalist, 1881, p. 1018. 
Pachycena ossifraga Cope. Report Capt. Wlieeler, U. S. G. G. Surv. W. 
of 100th Mer. iv, ii, p. 94, 1877. 
A series of specimens of this species demonstrates the following points : 
(1) Pachycena was founded on a superior molar of Mesonyx, and must be 
suppressed. (2) Mesonyx navajovius Cope must be separated as a distinct 
genus, since the apices of the crowns of the. last two molars have two 
cusps. I have called this genus Dissacus (American Naturalist, Dec., 1881). 
(4) It results that there are three species of Mesonyx : M. ossifragus 
Cope, M. lanius Cope, and M. obtusidens Cope. 
M. ossifragus was the largest Creodont of the Eocene, equaling the 
largest grizzly bear in the size of its skull. In a cranium with lower jaw 
and almost complete dentition, the length to the premaxillary border from 
the post glenoid crest is M. .365 ; the largest TJrsus horribilis in my collec- 
tion gives .270 for the same length. This specimen has the dental formula 
I. § ; C. |; P-m. \ ; M. f. The claws have the flattened form which I 
discovered in M. lanius, and the proximal phalanges have much the shape 
of those of a Perissodactyle. The astraglus has much the character of the 
animals of that order, and has the distal facets as I originally detected 
them in the M. obtusidens. The form of this bone is rather shorter and 
wider than in the latter species. 
The inferior canine tooth of a large specimen has the following diameters 
at the base of the crown : anteroposterior .039 ; transverse .024. 
AMBLYPODA. 
Pantodonta . 
The explorations in the bad lands of the Big-Horn river yielded several 
species of this sub-order, all which I refer at present to the Goryphodontidce. 
They, however, represent several genera, two of which have not been 
previously knowrn. I have distinguished these (American Naturalist, Jan., 
1882), in the characters of the superior molar teeth as follows : 
I. Last superior molar with two interior cusps. 
All the superior molars with a well marked external posterior V 
Manteodon. 
II. Last superior molar with hut one inner cusp or angle. 
a. Last superior molar with posterior external cusp. 
Anterior two molars with posterior external Y Ectacodon. 
aa. Last superior molar without external posterior cusp, 
f Anterior twro molars with posterior external Y. 
Astralagus transverse, with internal hook Coryphodon. 
Astragalus subquadrate, without internal hook Bathmodon. 
f+First superior molar only with posterior external V Metalophodon. Cope.] 
166 
[Dec. 16, 
The type of Manteodon is the M. subquadratus, which was about the size 
of an ox. The characters of its superior molars are more like those of 
Perissodactyles than are those of the other Coryphodontidce. The type of 
Ectacodon is the E. cinctus, a species of about the dimensions Of the last 
named. Its last superior molar is parallelogrammic, and has a cingulum 
all around it except on the external side. 
Manteodon suixquadratus, gen. et sp. nov. 
Char. gen. These have been already pointed out in the key above given. 
They are a little more like those of the superior molar teeth of such 
Perissodadyla as Limnohyus and near allies, than those seen in the typical 
Coryphodon. The posterior transverse ci'est of that genus is here i-ep- 
resented by a complete Y, but the anterior lobe of that crest which repre- 
sents the anterior Y of the Perissodactyle, is only a lobe, as in Coryphodon. 
The tooth in fact is much like the penultimate molar of the latter genus. 
The two internal cusps are unique in the family. The additional one is a 
growth of the inner extremity of the posterior cingulum, and is separated 
from the anterior inner cusp by a deep and wide notch. It is opposite to 
the posterior Y, as the anterior inner cusp is opposite the anterior rudi- 
mental V. The premolar and incisor teeth are similar to those of Coryphodon. 
The skeleton is unknown. 
Char, specif. These are learned from a series of teeth which were found 
together by Mr. Wortman free from admixture of others. They are not 
woi'n, excepting by moderate use of the animal when living. 
The last superior molar is not of the oval form belonging to the species 
of Coryphodon, but is quadrate, with the internal side shorter and with 
rounded lateral angles. The first antei'ior cingulum, which represents the 
anterior basal cingxilum of the Lophiodontidm, is as elevated as in the 
species of Coryphodon. Externally it rises in a protuberance with sharp 
edge, which curves posteriorly and disappears on the external side of the 
crown. The inner extremity terminates abruptly, forming the anterior 
interior tubercle. The anterior external lobe is rather flat, and is not conical 
nor elevated above the anterior cingular lobe. It is not deeply sepai’ated 
from the latter, nor from the posterior V ; its edge is rough. The posterior 
V projects well inwards, and is rather narrow. Its posterior boi'der ex- 
tends as far outwards as the point of junction of its anterior border with 
the anterior external lobe, and terminates in a slight elevation of its border. 
The base of the crown extends external to the base of the V, and forms a 
strong posterior external protuberance. This causes the outline of the 
external base to be concave. This side of the crown has several small 
protuberances and rugosities. The posterior basal cingulum extends as 
far extei'nally as the posterior Y, and terminates internally in the posterior 
internal cusp. The second or basal anterior cingulum is well developed. 
There are no external nor internal cingula. The surface of the enamel is 
strongly and closely rugose where not worn. 
The posterior inferior molar exhibits a transverse posterior crest, without 1881.] 
167 
[Cope. 
any tubercle or ridge in the mouth of the posterior Y-shaped valley. There 
is a strong posterior cingulum, amounting to a narrow heel. As in the 
case of the superior molar, the enamel where not worn is closely and 
strongly wrinkled. The first superior premolar is characterized by the 
very small development of its internal lobe, which is only a strong basal 
cingulum. The crown proper has a sub-triangular outline, and the ex- 
ternal face is flat and not concave. No external cingulum ; enamel 
wrinkled. An external incisor has a large transversely extended crown, 
without cingula. A low rib on the median line of the inner side. Enamel 
wrinkled. In this and in another incisor, the base of the crown is con- 
siderably expanded laterally. 
Measurements. 
M. 
Diameters of crown M. Ill, sup. 
anteroposterior 035 
transverse 041 
vertical 020 
Width of M. Ill inferior, posteriorly 022 
anteroposterior 018 
transverse 014 
Diameters P-m. I sup. 
Diameter base crown I, II 024 
Length crown I, II 019 
Width base crown I, III 026 
Ectacodon cinctus, gep. et sp. nov. 
Char. gen. In Ectacodon the last superior molar has more of the ele- 
ments of a posterior external Y than in Coryphodon, but not so much as 
in Manteodon. The posterior transverse crest, it is true, has no oblique 
posterior ridge joining it, to form with it more or less of a Y. But the 
external posterior angle of the crown supports a cusp, homologous with 
the vertical rib found at the basal or external angles of the Ys in Paleeosyops 
and allied genera, and indicating the outlines a Y which lacks its pos- 
terior side, in a manner not seen in Coryphodon. The penultimate and 
ante-penultimate superior molars are like those of the latter genus. Skele- 
ton unknown. I have a single species of this genus. 
Char, specif. Six superior molars of one skull represent this species. 
They belong to a large animal, one about the size of the Manteodon sub- 
quadratus. The last superior molar has a characteristic outline. It is not 
oval as in the species of Coryphodon, nor quadrate as in Manteodon sp., 
but sub-parallelogrammic. The transverse diameter exceeds the antero- 
posterior, and the anterior and posterior sides are parallel. The external 
outline is slightly oblique and slightly notched in the middle. The internal 
border is regularly rounded. The basal or second cingulum extends en- 
tirely round the tooth from the posterior external cusp, round the inner 
base to the anterior external base of the crown ; being absent only from 
the external base. The first cingula both anterior and posterior are well 
developed as in the species of Coryphodon, and unite in the prominent 
internal angle. The posterior first cingulum joins the posterior basal cin- Cope.] 
168 
[Dec. 16, 
gulum at the middle of its length. The anterior first cingulum extends 
to the anterior external part of the crown, and then turns downwards and 
posteriorly and terminates at the middle of the external base. The 
posterior crest is not transverse, but quite oblique, sloping at an angle of 
45° with the axis of the jaw. The part of the crest which represents the 
posterior V is a good deal larger than the part representing the anterior 
V, and is closely joined with it. The latter is well separated from the 
anterior first cingular ridge and its anterior exterior elevated portion. The 
enamel of this tooth is finely wrinkled, and is more readily worn smooth 
than in the Manteodon subquadratus. 
The penultimate superior molar has the posterior V well developed, 
and its posterior basal or external angle is marked by a tubercle homol- 
ogous with that which is 90 prominent on the last molar. The anterior 
Y is a conic tubercle closely joined with the posterior Y, and well separated 
from the anterior first cingular lobe. The basal cingular are well developed, 
but do not meet on the inner base of the crown. The first or superior 
cingula meet as usual in an interior angle, but there is a contraction of the 
anterior crest just before reaching this angle. The first true molar is 
smaller than the second and has the same general structure. Here, how- 
ever, the anterior first cingulum is more prominent near the internal angle 
than the posterior. The characters of the premolars do not differ from 
the corresponding ones of species of Coryphodon. The enamel is delicately 
wrinkled. The first superior premolar is not preserved. 
Measurements. 
ant eroposterior 034 
transverse 043 
vertical 015 
M. 
Diameters of crown of M. Ill 
ante roposterior 028 
transverse 033 
vertical 012 
Diameters M. I 
Diameters P-m. Ill 
anteroposterior 023 
transverse 030 
It is probable that this species was about the size of an ox. 
CORYPHODON ANAX, 8p. nOV. 
Mr. Wortman sends me a number of teeth of probably two individuals, 
which exceed in size those of any species of Coryphodon yet known, and 
differ in certain details of form from all of them. The specimens consist 
of incisors, premolars and molars of both jaws of one animal, and an in- 
ferior canine, which from its separate wrapping, I suppose to have been 
derived from a different locality. 
The incisors and premolars have the form usual in species of the genus, 
differing only in their large size. The same may be said of the premokirs. 
A well preserved superior true molar is probably the third. It has the 
form usual in the genus, but exhibits two peculiarities. The posterior 
transverse crest is divided more deeply than usual by a deep notch which 3881.J 
169 
[Cope. 
enters it from the transverse valley. The external portion is the shorter, 
and exhibits the peculiarity of being connected with external part of the 
anterior transverse crest. It is as closely connected with this crest, as it 
is with the internal portion of the posterior crest. The external connec- 
tion does not exist in the other species of the genus, where the two crests 
are separated at their outer extremities by a deep valley. The posterior 
basal cingulum is obsolete, while the anterior is well developed. The 
enamel of this tooth where not worn, is wrinkled. 
The posterior part of the last inferior molar is characteristic. The 
posterior transverse crest is short and very oblique, its inner extremity 
striking the posterior margin near the middle. Here it is elevated into a 
cusp, which rises above the surrounding parts in a characteristic manner. 
There is no ledge round its posterior base, but the border expands out- 
wards at the base of the true crest. The additional inner marginal 
tubercle is low and compressed as in C. lobatus. A second inferior true 
molar is normal, with well developed anterior marginal ridge. The in- 
ferior canine mentioned is of large proportions, exceeding by one half 
the dimensions of the inferior canine of G. lobatus. Its crown is curved 
outwards, and has a basal alate expansion of its internal ridge. 
MeasurementsJ 
M. 
Diameters of last superior molar 
anteroposterior 039 
transverse 051 
Diameters of second inferior true molar 
anteroposterior .039 
transverse 028 
Length of inferior canine .160 
“ crown of “ 090 
Diameters of base of crown of canine 
vertical 037 
; transverse 036 
This species is nearest the C. lobatus in some respects. The short posterior 
crest ot the last inferior molar with its cusp-like extremity, and the absence 
of posterior ledge on this tooth will readily distinguish it. 
Bad lands of the Big-Horn river, Wyoming. 
There are six individuals of this species in the collection which are 
mostly represented by fine specimens, which represent the entire denti- 
tion . 
Eight other species of Caryphodon were obtained by the Big-Horn Ex- 
pedition, and the material enables me to distinguish them better than here- 
tofore. I present the following differential synopsis of their characters. 
I. The last inferior molar with three posterior cusps, the internal some- 
times represented by a ridge ; or the posterior inferior molars with 
an accessory cusp or tubercle on the inner side between the crests 
(Caryphodon, Owen) : 
An internal tubercle ; last upper molar with the anterior cross crest and an- 
terior external crest closely connected ; size largest C. anax. Cope.J 
170 
[Bee. 1C, 
An internal conic cusp ; posterior crest oblique ; heel very small ; size 
medium G. cuspidatus. 
An internal crest; posterior crest oblique; heel small; size medium 
C. obliquus. 
An internal tubercle ; posterior crest little oblique ; heel large ; size large. 
C. lobatus. 
II. Posterior inferior molars with two posterior cusps ; without internal 
accessory tubercle : 
a. Posterior inferior molars with small or no heel: 
Large; posterior superior molar oval, with distinct straight posterior 
crest; inferior molars elongate ; symphysis mandibuli produced and 
narrowed; premaxillary elongate G. latipes. 
Medium ; inferior molars nearly as wide as long ; premaxillary short 
G. latidens. 
aa. Posterior inferior molars with prominent or wTide heel: 
Medium ; posterior superior molar with posterior angle, and angulate 
posterior crest ; inferior molars elongate ; symphysis mandibuli broad 
and short ; premaxillary elongate ; tusk trihedral G. elephantopus. 
Smaller ; premaxillary bone short; tusk trihedral C. simus. 
Medium ; premaxillary elongate ; tusk compressed and grooved 
G. molestus. 
Large ; last superior molar oval, with angulate posterior crest; its anterior 
lobe connected with anterior cingular crest G. repandus. 
III. Last inferior molar with but one posterior cusp from which a curved 
crest extends round the posterior border of the crown. 
Superior true molars narrow ; external incisors sharply angulate on ex- 
ternal face...' G. curvicristis. 
IV. Posterior inferior molar unknown. 
Posterior superior molar oval; posterior crest straight; internal crest 
fissured (? normally) ; a complete internal cingulum... G. marginatus. 
CORYPHODON CUSPIDATUS Cope. 
This species was found in a single individual obtained in New Mexico ; 
a second one was discovered by Mr. Wortman in the Wind River basin, 
and a third has now been brought from the Big-Horn. 
CORYPHODON LATIPES Cope. 
I refer seven individuals provisionally to this species. Three of these 
are represented only by superior teeth, etc., and in four the last inferior 
molar is preserved. Of the latter, three have an angle, sometimes almost 
a crest, descending from the posterior inner tubercle, as in C. obliquus, but 
the specimens are all of superior size to that species, some of them very 
much exceeding it. It is also possible that this ridge is not a constant 
character. This species has the dentition which I have referred to the 
Bathmodon radians, but no astragalus of the species occurs in the collec- 
tion. It may be the C. latipes, of which the teeth have not yet been iden- 
tified. I hope soon to be able to decide this question. 1881.] 
171 
[Cope. 
CORYPHODON SIMUS Cope. 
A broken mandible and maxillary bone, with several teeth represent 
this small species in the Big-Horn collection. 
CORYPHODON ELEPHANTOPUS Cope. 
Portions of the dentition of both jaws, including the last molar teeth 
of two individuals, prove that this species inhabited Wyoming in the early 
Eocene period. One of the individuals, represented only by the last 
molars of both jaws, is a little smaller than the typical specimen of which 
an entire cranium is figured in Capt. Wheeler’s report (4to, 1877, PI. 
LI-III), while a second specimen, which includes the entire superior 
molar series, is a little larger than the same. 
This species is characterized by the obliquity of the edge of the posterior 
crest of the posterior superior molar backwards away from a transverse 
line ; and by the slope of the external side of this crest. In other words 
the inner half of the posterior crest nearly forms a Y, like that of the 
penultimate molar. The posterior edge of the Y is present, running out- 
wards from the inner end of the posterior crest, which thus becomes the 
apex of the Y. The G. elephantopus thus most nearly approaches the 
genus Manteodon, of all the species. To accommodate the obliquity of 
the crest the posterior outline of the last upper molar is strongly angulate, 
giving a sub-triangular outline. The heel of the last inferior molar is 
insignificant. 
CORYPHODON REPANDUS, Sp. nOV. 
This large species is known from the posterior portions of the dentition 
of both jaws, with an entire symphysis. 
The last superior molars are intermediate in outline between the regular 
oval of the G. radians, and the sub-triangular form of the G. elephantopus. 
The peculiarities of the species are seen in the posterior crest. The two 
lobes of which this is composed, do not form a continuous line as in C. 
latipes and C. simus, but form an angle with each other as in G. anax. 
The anterior lobe is compressed, and its long axis is nearly that of the jaw ; 
the second lobe leaves it at a right-angle, but curves backwards as it ex- 
tends inwards, giving a concave exteroposterior border. There is no ridge 
descending outwards from the inner extremity of the crest, to form a V, 
as in C. elephantopus. But the posterior basal cingulum extends to 
the external side of the tooth, which is not the case in any other species 
known to me excepting the C. marginatus. The anterior cusp is closely 
joined to the external elevation of the anterior first cingulum as in G. anax ; 
a character which separates it from all other species. A strong trace of a 
cingulum passes round the inner base of the crown. No external cingulum. 
The first true molar does not differ materially from that of other species. 
It is considerably smaller than the last. The apex of the premaxillary 
bone with the second incisor and alveolus of the first, is preserved. The 
bone is rather short. The crown of the incisor is regularly convex ex- Cope.j 
172 
[Dec. 16, 
ternally, and is not expanded at the base. There is a strong internal 
cingulum. 
A fragment of the lower jaw supports the last two molars. The internal 
angle of the last one, is unfortunately broken. The posterior crest is, 
however, perfectly transverse, which is not the case with the species with 
three posterior tubercles. The preserved part of the posterior border shows 
a distinct, rather narrow heel. The anterior Ys are well developed and 
there are no lateral cingula. The symphysis is flattened out by pressure. 
The inferior canine is large. It is sub-triangular at base and has an anterior 
basal angular projection. 
Diameters of superior M. Ill 
Measurements. 
transverse 046 
longitudinal 037 
M. 
transverse 086 
longitudinal 032 
Diameters of superior M. I 
vertical 018 
transverse 018 
Diameters crown I. 2 
transverse 028 
anteroposterior 040 
vertical in front (restored).. .024 
Diameters inferior M. Ill 
Length of symphysis 107 
Depth of ramus at M. Ill 056 
The superior molars of this species might readily be taken for an under- 
sized individual of C. anax, but the last inferior molar is of a different 
type, and refers the species to a different section of the genus. 
CORYPHODON CURVICRISTIS, Sp. nOV. 
The fragments which represent this species belong to one individual. 
They include a considerable part of both mandibular rami with numerous 
molar teeth, and most of the inferior incisors loose. Also the second 
superior molar, some superior premolars, the canine, and three or four 
incisors, two of them in place in an incomplete premaxillary bone. None 
of the bones of the skeleton were obtained, so far as known. 
The ramus of the mandible is both robust and deep. Its inferior border 
does not rise posteriorly so much as in some species, as e. g., C. latidens, 
and the angle is well below the horizontal line of the dental alveoli. The 
dental foramen is just about in this line. The inferior premolars and 
molars do not differ from those of several other species, but the last molar 
has several peculiarities. The external cusp is the only one of the posterior 
pair which is present. It gives origin to two crests, both of them curved. 
The posterior represents the usual posterior transverse crest, but is gently 
convex backwards, and turns forwards on the inner side of the crown, 
only terminating at the external base of the anterior cross crest. The 
other curved crest is low, although higher than in most species, and ex- 
tends to the middle of the base of the anterior cross crest. There is a dis- 
tinct heel which is elevated at the middle and disappears gradually at each 
end, not being abruptly incurved as in G. anax. The anterior part of this 1881.) 
173 
[Cope 
tooth is as peculiar as the posterior. The external cusp gives origin to 
three crests, two of them the usual limbs of the anterior V ; while a third 
descends to the anterior border a little exterior to its middle. It encloses 
a deep groove with the anterior ridge of the anterior V. This arrangement 
is not seen in any other species. 
The inferior canine is robust, and has its anterior angle prominent, but 
not alate. The crowns of the inferior incisors are regularly convex ex- 
teriorly, and have no cingula. They are regularly graded in dimensions. 
The superior molar preserved is probably the penultimate. Its 
anterior portion is broken. The posterior external V is narrower 
than usual for a second molar, and resembles somewhat that of the 
last superior molar of the Manteodon subquadratus. A slight contact 
face on the posterior cingulum shows that this tooth is not the last 
molar. The said cingulum extends to the external base of the V; in 
rising to the internal cusp it forms a sigmoid curve. The cingulum 
below this, on the inner base of the crown, is rudimental. The superior 
canine has a long and robust crown, with a triangular section to the apex. 
The posterior face is a little wider than the other two, which are equal. 
The anterior is slightly concave in cross-section, and the posterior slightly 
convex transversely, although concave longitudinally. There is a weak 
ridge nearly parallel to and near the postero-external angle, and traces of 
others on the postero-external face of the crown in front of this one. The 
antero-internal angle is swollen at the base. 
The superior incisors present characteristic features. The ridge of the 
external face, which is weakly developed in some of the species, and is 
wanting in others, is here represented by a strong longitudinal angle, 
which extends from the base of the crown to its apex, dividing the 
external face into tA\ro distinct planes. This character is most marked on 
the external incisor, where*the planes are sub-equal, and concave. On the 
second the anterior plane is smaller, and on the first it is a good deal 
smaller. These incisors have a weak internal cingulum, but no external one. 
Length of ramus from P-M. IV inclusive 257 
“ inferior true molars 098 
Measurements. 
M. 
anteroposterior 0275 
transverse 020 
Diameters of M. I infer. 
Diameters of M. Ill infer. 
anteroposterior 036 
transverse 029 
Depth of ramus at M. Ill 075 
anteroposterior 0315 
transverse 039 
Diameters of M. II super. 
longitudinal... .094 
anteroposterior. .022 
transverse 034 
Diameters of crown of superior canine 
Diameters of crown of I. iii 
vertical 022 
transverse .024 Dope.] 
174 
[Dec. 10, 
The numerous characteristic marks, show that this species is one of the 
most distinct of the genus. It is also one of the largest, being second only 
to the C. anax. 
CORYPHODON MARGIN AT US, sp. nOV. 
This is one of the smaller species, having nearly the dimensions of the 
C. molestus. It is only represented by the superior canine, first inferior 
premolar, and last superior molar of one individual found together by Mr. 
Wortman. Their size, mineral condition and degree of wear, render it 
probable that all belong to one individual. 
The superior molar is of the oval type, without posterior shoulder. The 
posterior crest is therefore straight, and parallel with the anterior crest. 
Its inner extremity does not display the least tendency to form a Y, as is 
seen in C. elephantopus. Its exterior extremity is widely separated from 
the external prominence of the anterior crest (cingulum). The latter dis- 
plays, at its inner extremity, the peculiarity of a deep fissure of the anterior 
side, which nearly divides the crest, and partially isolates the internal 
tubercle. Adjacent to the fissure its crest is tuberculate. The posterior 
upper cingulum descends from the inner cusp to the basal cingulum. The 
basal cingulum is well developed on the anterior and interior sides of the 
crown, and on the posterior as far as the base of the inner cusp of the 
posterior crest, where it gradually fades out. Enamel wrinkled. 
The superior canine is remarkable for its small size. The posterior face 
is a little the widest, and its bounding edges are sharp, but not expanded. 
There are no prominent ridges of the enamel. The anterior face is mode- 
rately wide. The first inferior premolar presents no peculiarities. 
Measurements. 
anteroposterior 028 
transverse 038 
vertical 019 
M. 
Diameters of M. Ill superior 
Diameters of P-m. I inferior 
anteroposterior 015 
transverse 009 
Diameters of C. superior 
anteroposterior 014 
transverse posterior 018 
The superior molar is but little worn, and shows that the animal was 
just adult. The canine is more worn than the molar. 
There are several characters which mark this species as distinct from 
those previously known. It is the only member of the genus which has 
a complete internal cingulum. The fissure of the anterior crest, if normal, 
is peculiar to this species. The superior canine is disproportionately 
small. 
Besides the Coryphodons already mentioned, a number of more (*r less 
complete skeletons were obtained, some of which can be identified by 
comparison with those which are accompanied by teeth, and which are 
enumerated in the preceding pages. 18 81.] 
175 
[Cope. 
Metalophodon testis, sp. nov. 
The genus Metalophodon was described by me in 1872.* Since that 
time it lias remained without further illustration of importance, as no good 
specimens of it have been obtained by any of my expeditions up to the 
present year. Thy material now at hand consists of the entire superior 
molar series of the right side, and the superior molars of the left side, in 
beautiful preservation. These display the characters on which the genus 
was proposed, i. e., the conversion of the posterior external V of the 
second true molar into a transverse crest similar to that of the last true 
molar. It follows that the first true molar is the only one which exhibits 
this V. It also follows that in this genus the peculiarities of the dentition 
of Coryphodontidce are carried further than in Coryphodon, where two 
molars display the V, and one the crest; or than in Manteodon, where all 
three have a V, and none the crest. The genera then stand in the order 
of evolution, Manteodon, Coryphodon, Metalophodon. 
Char, specif.—The first superior premolar has lost its crown. The other 
premolars do not display any marked peculiarities. The internal cusps 
are well developed, and are most prominent posterior to the line of the 
apex of the exterior crest. They connect with the posterior cingulum by 
a broad ledge, but do not connect with the anterior cingulum. The two 
cingula nearly connect round the inner base of the crown on the third 
premolar. 
The first true molar is well worn. The base of the posterior external 
Y can be seen, and the anterior and posterior cingula. There is no in- 
ternal cingulum. The second true molar is the largest of the teeth. It 
is subtriangular in outline, its external side forming with the posterior, a 
right angle. Its general character is much like that of the Corypliodontes, 
but it presents the remarkable exception which constitutes the character 
of the genus Metalophodon. The posterior crest does not include a V, but 
is straight, and consists of the same elements as the posterior crest of the 
third true molars, but differently proportioned. The part representing the 
anterior V is a cone, much shorter than the part corresponding to the 
posterior V. As there is a postero-exterior angle of the crown there is an 
oblique surface rising to this part of the crest, which represents the ex- 
ternal face of the y. There is also a small tubercle at the angle, where a 
similar one is found in the corresponding tooth of Ectacodon cinctus. 
Altogether this tooth is like the posterior molar of Coryphodon elephantopus, 
with a more prominent postero-external angle added. The anterior and 
posterior basal cingula are well developed, the latter being strong in- 
teriorly to the point where it sends a branch upwards to the internal 
cusp. There is no internal cingulum. 
The last superior molar is a transverse oval, more regular than usual in 
the species of Coryphodon, since the diameters of the internal and external 
portions are about equal. The characters of the posterior crest differ from 
* Proceedings American Philos. Soc., 1872, p. 542. Cope.] 
176 
[Dec. 16, 
those seen in the genus named in that the internal portion is much smaller 
than the external, having a small conic apex, distinct from that of the 
exterior portion. Its postero-external face is nearly vertical, and it 
diverges a little posterior to parallel with the anterior crest. The latter 
(the first cingulum) is elevated, and is widely separated externally from 
the posterior crest, to whose base it descends on the external extremity of 
the crown. The basal cingulum is present all round the the crown except 
at the base of the posterior crest, and externally. It is narrow on the 
inner extremity of the crown. It sends upw ards a strong branch to the 
apex of the internal cusp. The enamel of all the molars is strongly 
wrinkled, but is worn smooth wherever rubbed. 
Length of superior molar series 179 
premolar series 085 
Measurements. 
M. 
f anteroposterior 019 
i. transverse 025 
Diameters P-m. II 
Diameters M. I 
anteroposterior 029 
transverse * .032 
Diameters M. II 
anteroposterior 036 
transverse 042 
Diameters M. Ill 
anteroposterior 0285 
transverse 041 
vertical 015 
The Metalophodon testis differs from the M. armatus, in the more 
triangular form of its penultimate superior molar. Its form is quite 
different from that of the last molar, while in M. armatus, the two teeth 
resemble each other closely. The species are of about the same size. 
The individual from which the above description is taken is rather aged. 
DlNOCEltATA. 
Bathyofsis fissideks Cope. 
Bulletin U. S. Geolog. Survey, Terrs., Feb. 1881, 194. 
A considerable part of the dentition of the mandible of this species was 
found in the Big-Horn bad lands. This includes an incisor tooth, which 
is quite characteristic, and renders it probable that the anterior parts of the 
jaws differ considerably from those of other Uintatheriidce. The root is 
sub-round. The crown resembles a good deal that of the species of Cory- 
phodontidai. It is higher than wide and has a subacute apex. One edge 
of the crown is convex, and the other concave. The external face is con- 
cave in both directions, and has no ridges nor cingulum. The inner face 
is concave longitudinally and convex transversely. The convexity is 
median and has a longitudinal concavity on each side of it. No internal 
cingulum except a trace at the base of the concave edge. The edges are 
obtuse even when unworn, and the enamel is obsoletely rugulose. 1881.] 
177 
tCope. 
Measurements of incisor. 
M. 
Diameters of crown 
anteroposterior 012 
transverse ; 020 
vertical 020 
anteroposterior 012 
transverse 014 
Diameters of root 
This incisor is very different from the kind seen in Loxolophodon. Mr. 
Osborne has shown that genus to have these teeth with compressed two- 
lobed crowns, a type unknown elsewhere among Mammalia.* 
PERISSODACTYLA. 
In a paper on the “homologies anti origin of the molar teeth of the 
Mammalia Educabilia,” published in March, 1874,f I ventured the gene- 
ralization that the primitive types of the Ungulata would be discovered to 
be characterized by the possession of five-toed plantigrade feet, and tuber- 
cular teeth. No Perissodactyle or Artiodactyle mammal was known at 
that time to possess such feet, nor was any Perissodactyle known to 
possess tubercular teeth. Shortly after advancing the above hypothesis, I 
discovered the foot structure of Coryphodon, which is five-toed and planti- 
grade, but the teeth are not of the tubercular type. For this and allied 
genera, I defined a new order, the Amblypoda. and I have published the 
confident anticipation that genera would be discovered which should possess 
tubercular (bunodont) teeth, This prediction has not yet been realized. 
I now, however, record a discovery, which goes far towards satisfying the 
generalization first mentioned, and indicates that the realization of the 
prophecy respecting the Amblypoda, is only a question of time. 
In 1878,| I described from teeth alone, a genus under the name of 
Phenacodus, and although a good many specimens of the dentition have 
come into my possession since that date, I have never been able to assign 
the genus its true position in the mammalian class. The teeth resemble 
those of suilline Ungulates, but I have never had sufficient evidence 
permit its reference to that group. Allied genera recently discovered by 
me, have been stated to have a hog-like dentition, but that their position 
could not be determined until the structure of the feet shall have been as- 
certained. § 
In his recent explorations in the Wasatch Eocene of Wyoming, Mr. J. 
L. Wortman was fortunate enough to discover nearly entire skeletons of 
Phenacodus primeevus, and P. vortmani, which present all the characters 
essential to a full determination of the place of Phenacodus in the system. 
The unexpected result is, that this genus must be referred to the order 
Perissodactyla, and that with its allies, it must form a special division of 
that order corresponding in the tubercular characters of its teeth with the 
* A Memoir on Loxolophodon and Uintalherium. By H, Osborne, 
t Journal of the Academy of Natural Sciences, Philadelphia. 
Palaeontological Bulletin No. 17. Oct., 1873, p. 3; also, Report G. M. Wheeler, 
U. S. Engineers Expl. W. 100 Mer., iv, p. 174—1877. 
Proceedings Anier. Philos. Society, 1881, p. 495. Cope.] 
178 
[Dec. 16, 
bunodont or suilline division of the Artiodactyla. In this character, how- 
ever, there is a closer gradation than in the case of the Artiodactyla, and it 
would scarcely be necessary to create such a group on that character alone. 
But the genus differs further from the Perissodactyla and approaches the 
Proboscidia, in the fact that the astragalus articulates with the navicular 
only, and by a universally convex surface, as in the Carnivora. 
The astragalus resembles that of the latter order very closely, and differs 
from that of Hyracotherium and the nearest forms among the Perissodactyla. 
Phenacodus has moreover five well developed toes on all the feet, and was 
probably not entirely plantigrade. The cast of the brain case shows that 
the cerebral hemispheres were quite small and nearly smooth, and that the 
very large cerebellum and olfactory lobes were entirely uncovered by 
them. The bones of the two carpal rows alternate with each other, and 
there is a large third trochanter of the femur. The cervical vertebrae are 
opisthoccelous. 
This group is then the ancestral type of the known Perissodactyla, that 
is of the horses, tapirs and rhinoceroses, and of the numerous extinc 
forms. Its systematic position may be schematically represented as 
follows : 
Order Perissodactyla ; ungulate ; digits of unequal lengths ; carpal 
bones alternating; a postglenoid process. Astragalus with proximal 
trochlea, and without distal double ginglymus. 
Suborder Diplarthra ; astragalus distally plane or concave in one direc- 
tion, and uniting with both navicular and cuboid bones : a third trochanter 
of the femur. The known families belong here. 
Suborder Condylarthra; astragalus convex in all directions distally, 
only uniting with navicular bone ; a third trochanter of femur. 
Family Phenacodontidce. Molar teeth tubercular ; the premolar teeth 
different from the molars ; five digits on all the feet. 
Genera; Phenacodus Cope, and very probably Catathlceus, Anacodon and 
Protogonia Cope, and perhaps also Anisonchut Cope. These genera include 
fifteen species, all from the lower Eocene beds. I gave a synopsis of their 
differential dental characters in the Proceedings of the Philosophical Society, 
1881, p. 487, where I included also the genus Mioclcenus. I omit the latter 
from the family at present, as I believe it to be Artiodactyle. 
Phenacodus erimacvus Cope. 
Parts of a dozen individuals of this species were obtained, and one 
almost entire skeleton in a block of soft sandstone. This includes nearly 
all parts of the four extremities, as well as the skull, from which but small 
portions are wanting. 
Species of this genus, so far as determinable from the dentition, are 
numerously represented in Mr. Wortman’s collection. About fifty individ- 
uals are referable to eight species. These present a great range in size, 
and some diversities of structure. They may be distinguished as follows : 1881.J 
179 
[Cope. 
I. Last inferior molar with oval outline; heel small; anterior inner 
cusp simple. 
Size medium ; length of true molars .025 ; depth of ramus at M. II, .018. 
P. apternus. 
II. Last inferior molar wedge-shaped, with heel prominent; anterior 
inner cusp simple. 
Large ; true molars .041 ; P-m. IY .014 ; depth of ramus at M. II, .027. 
P. primoevus. 
Medium ; true molars .027 ; depth at M. II .017 ; last molar smaller 
P. vortmani. 
Smaller; true molars .022 ; depth at M. II .018 ; last molar elongate ;.. 
P. macropternus. 
Smaller ; last four molars .027 ; P-m. IV .007 ; depth at M. II .013 ; last 
molar with short heel P. brachypternus. 
Smallest; true molars .017 ; depth at M. II .012 ; heel long ; cusps ele- 
vated P. zuniemis. 
III. Last inferior molar wedge-shaped, with prominent heel ; anterior 
inner cusp double ; 
Least ; last inferior molar .006 ; heel narrow ; true molars (superior) .016. 
P. laticuneus. 
Two other species have been described, the P. sulcatus, and P. omnivorus 
Cope. The former I suspect belongs to another genus. I am not now 
sure of the distinctness of the latter from P. primmus. 
Phenacodus hemiconus, sp. nov. 
Represented by the posterior two superior molars of an individual in- 
termediate in size between the P. primeevus and P. puercensis. The pos- 
terior molar is peculiar in the very rudimental character of the posterior 
internal lobe, which is reduced to a mere wart on the cingulum. The 
posterior external tubercle is also rudimental, not exceeding the posterior 
inner in dimensions. The anterior tubercles, including the intermediate, 
are well developed, the internal exceeding the external. The cingulum 
is wide and crenate, and is only wanting on the external base of the crown. 
The penultimate molar does not differ so much from that of P. primeevus, 
but the two internal cones are not so deeply separated at their base. The 
tubercles are all but little worn, and are conical in form, the external 
flattened on the external faces. Enamel wrinkled. 
Measurements. 
M.* 
Diameters of M. II 
anteroposterior 009 
transverse 012 
Diameters of M. Ill 
anteroposterior 010 
transverse 018 
The size of this species precludes the possibility of its identity with any 
of the other species described here. 
Phenacodus wortmani Cope. Bulletin U. S. Geol. Surv. Terrs, vi, 
1881, p. 191). Hyracotherium vortmani, American Naturalist, 1880, p. 747. Cope.] 
180 
[Dec. 16, 
Phenacodus puercensis Cope. Proceeds. Amer. Philos. Soc. 1881, p. 492. 
An abundant species, represented by twelve mandibular rami in the 
collection, and by a nearly entire skeleton with perfect skull. 
Phenacodus apternus, sp. nov. 
Three rami, each of which supports the true molar teeth, indicate this 
species. The oval form of the posterior molar is due to the shortness of 
the heel, and the large size of the internal median tubercle, which pro- 
jects inwards, giving a convex outline to the interior side of the crown. 
The external tubercles of all the true molars wear into crescents ; and the 
anterior inner is more robust than the posterior inner. 
Phenacodus macropternus, sp. nov. 
This species is apparently rare, being represented by only one man- 
dibular ramus, which supports the posterior three molars, and a possible 
second ramus with molars iv and v. The first and second true molars 
are much like those of P. vortmani, but the third is relatively larger, and 
has an especially elongate heel. In P. vortmani the last molar is con- 
stricted, and narrower than the penultimate. In P. macropternus there 
is a weak external, and no internal cingulum. The tubercles of the last 
two molars are quite regularly conical, while the external pair of the first 
molar, wear into crescents. Smaller than the P. vortmani. 
Phenacodus brachypternus, sp. nov. 
Three mandibular rami are the only specimens of this species found by 
Mr. Wortman in the Big-Horn region. They all display the fourth pre- 
molar, which has the characters of this genus, as distinguished from 
Mioclamvs. The species is materially smaller than the P. vortmani, and 
its last inferior molar is intermediate between those of the latter and the 
P. apternus, in form. Both the internal and external intermediate tuber- 
eles are very full, and give the tooth width. The posterior or 
fifth tubercle is large, and gives the posterior outline of the crown a tri- 
foliate form. The posterior median tubercles of the M. II and I, are well 
marked. The molars gradually increase in size forwards, and the fourth 
premolar is longer than any of them, and rather narrow. The heel of the 
P-m. Ill is short and wide. On the true molars a weak external cingu- 
lum. Enamel slightly wrinkled. 
Phenacodus zuniensis Cope. Proceeds. Amer. Philosoph. Society, 
1881, p. 462. 
Mr. Wortman obtained eleven mandibular rami of this species, in only 
one of which are the premolars preserved. Excepting the P. laticuneus, 
this is the smallest species of the genus. The molars have much the ap- 
pearance of those of the Mesodont genus Hyopsodus, but may be dis- 
tinguished by the size of the posterior median tubercle. The second 
true molar is the widest tooth, and the last molar is rather elongate, and 
its cusps are not exactly opposite to each other. The cusps of the molars 1881.] 
181 
[Cope. 
are more elevated than in the other species, and those of the external side 
all have a distinctly crescentic section. The anterior inner cusp is narrow 
and simple. There is no cingulum of any kind. 
This species was originally described from New Mexican specimens. 
PlIENACODUS LATICUNEUS, Sp. nOV. 
This is the least species, and is represented by six superior molars and 
the last inferior molar in a fragment of the low er jaw. The latter tooth 
exhibits peculiar characters already mentioned. The superior molars 
differ from those known to belong to the P. primmus and P. puercensis in 
having a vertical fissure of the inner side which separates the bases of the 
two internal tubercles. This gives them some resemblance to the superior 
molars of the species of Anisonchus, but the important difference remains 
in the separation of the anterior inner tubercle from the intermediate 
tubercles. The three are confluent into a V in the genus last mentioned. 
The external cusps of the superior molars are rather acute, and lenticular 
in section, their external sides forming a convex rib. There is no rib 
between the external sides. There is a strong anterior cingulum, which 
terminates externally in a low angular cusp. There is no cingulum on 
any other part of the crown. The second, third and fourth premolars have 
two external cusps, and much resemble the corresponding teeth in Ilyraco- 
therium. The second is longer than wide, and has an internal ledge ; the 
third is as wide as long and has a wride internal ledge ; the fourth is wider 
than long and has an internal, and two intermediate cusps, and an anterior 
and posterior cingulum. They all have a weak external cingulum, of 
which a trace exists in the true molars. 
The last inferior molar has a double anterior inner cusp as in some 
Mesodonta, and the external anterior cusp is robust. All the cusps are 
conical and with round section, and their bases are close together. The 
outline of the base of the crowTn is almost an isosceles triangle with rather 
wide base in front. 
Measurements. 
M. 
Length of last six superior molars 0850 
“ true molars 0160 
Diameters of M. II 
anteroposterior 0055 
transverse 0080 
Long diameter base of P-m. II 0050 
Diameters P-m. Ill 
anteroposterior 0060 
transverse 0060 
Anacodon ursidens, gen. et sp. nov. 
Char. gen. Known only from mandibles supporting molar teeth. Prob- 
ably family Phenacodontidce, Last inferior molar with heel. Crowns of 
molars without distinct cusps, but with a superior surface consisting of 
two low transverse ridges separated by a shallow valley. Unworn grind- 
ing surface with shallow wrinkles. Perhaps only three premolars. Cope.] 
182 
[Dec. 10, 
Char, specif. Broken mandibular rami of two individuals constitute 
the basis of my knowledge of this species. It is of the size of the Phena- 
codus primeevus. The last inferior molar is wedge-shaped with the very 
obtuse apex posterior. It displays two slight transverse elevations anterior- 
ly which represent the usual cusps. Grinding surface generally nearly 
flat. The posterior half of the crown of the penultimate molar is flat, and 
is separated from the anterior half by a transverse groove. Its surface is 
marked by shallow branching grooves. 
The molar preceding this one in the broken specimen is probably the 
first. It is possible from its slightly worn condition that it is the fourth 
premolar, but the form is that of a true molar. The surface of the crown 
is marked by shallow grooves not very closely placed. The three premolar 
teeth in advance of this tooth are broken off. Their bases are narrow. 
There are no basal cingula on the molars. 
Measurements. 
M. 
length of posterior true molars. 033 
Diameters of M. Ill 
anteroposterior 015 
transverse 010 
anteroposterior... 015 
ti'ans verse Oil 
Diameters of M. ? I 
Depth of ramus at M. II 030 
The characters of the teeth of this species are something like that of 
some of the Palceochceri of the Miocene, and resemble more those seen in 
some of the bears. 
Oligotomus osbornianus, sp. nov. 
Char. gen. Dental formula ; I. ?, C. ?, P m. ? J ; M. f. External faces 
of external lobes of superior molars separated by a ridge ; anterior ex- 
ternal cusp of cingulum little developed. Premolars of superior series 
different from true molars, with only one internal lobe. Fourth inferior 
premolar similar to the true molars. Cusps of inferior molars connected 
by diagonal ridges forming Vs. A diastema in front of the second pre- 
molar. 
This genus is a good deal like Lambdotherium, so far as known. Its 
superior molars are much like those of Aeoessus, and their intermediate 
and internal tubercles are those of Hyracotherium. 
The two or three species known to me are of small size. 
Char. spec. The true molars of both maxillary bones, with the fourth 
premolar of one side are preserved more or less perfectly, with four in- 
ferior molars on two fragments of the lower jaw. 
The external tubercles of the superior molars are nearly erect, and have 
a lenticular section. The rib which separates their external faces is 
prominent, and terminates in a free apex. The base of each face is marked 
by a strong cingulum, but the posterior one is very short. There is a strong 
anterior basal cingulum, but no posterior or internal one. The anterior 
;nner tubercle is larger than the posterior. The intermediate tubercles are 1881.] 
183 
[Cope. 
sub-round, and are anterior to the transverse line of the interior ones. 
They do not join the latter excepting after very considerable wTear. The 
external anterior cingular cusp is rather more prominent on the first than 
on the second true molar. The fourth superior premolar has a well marked 
external anterior cingular cusp, which is, however, low ; and there is no 
ridge dividing the external faces of the external cusps. The single inner 
cusp is connected with the two external by two ridges, which diverge as 
they extend outwards. The anterior supports a tubercle close within the 
anterior external. There are strong anterior and posterior basal cingula 
and weak external and internal ones. 
The third inferior premolar has a compressed ridge on the heel. The 
fourth premobir is like a true molar, with the anterior inner cusp well de- 
veloped and elevated, and connected with the anterior and posterior ex- 
ternal by oblique ridges. The inner posterior cusp is less conic in form 
than in the true molars, and the entire crown is somewhat contracted 
anteriorly. The true molars are characterized by the presence of a small 
median tubercle on the posterior border. There is a low external basal 
cingulum, which is wanting opposite the posterior cusp. Enamel generally 
smooth. 
Length of superior true molar series 0210 
Measurements. 
M. 
Diameters of superior M. II 
anteroposterior 0080 
transverse 0097 
Diameters of P-m. IV 
anteroposterior 0085 
transverse. 0085 
Length from inferior P-m. Ill to M. II inclusive 0290 
Diameters of P-m. IV 
anteroposterior 0080 
transverse 0050 
Diameters of inferior M. II 
anteroposterior 0075 
transverse 0060 
Depth of ramus between P-m. Ill anti P-m. IV 0150 
As compared with the 0. cinctus,* this species differs in its superior 
dimensions. The anterior inner cusp of the inferior molars is probably 
single, though the slightly worn condition of those teeth renders this 
point a little uncertain. In 0. cinctus some of them at least are double. 
This species was, to judge from the size of its teeth, about the size of a 
red-fox. The specimens of it above described were found by Mr. J. L. 
Wortman in the bad lands of the Big-Horn river, Wyoming. It is dedi- 
cated to my friend, Henry L. Osborne, of Princeton College, New Jersey. 
Systeaiodon tapirintjs Cope. American Naturalist, 1881, p. 1018. 
Hyracotherium tapirinum Cope. Systematic Catalogue of the Eocene 
Vertebrata of New Mexico, 1875, p. 20. Report U. S. Geol. Surv. W. of 
100th mer. Capt. G. M. Wheeler, iv. ii. p. 263. PI. lxvi. figs. 12-16. 
This species was abundant in Wyoming during the Wasatch epoch, 
jaws and teeth of more than twenty individuals having been brought by 
* Annual Rept. U. S. Geol. Survey Terra. 1872. p. 607. Cope.] 
184 
[Dec. 16, 
Mr. Wortman from the Big-Horn. From these I learn that the dental 
system is different from that characterizing the species of Ilyracotherium. 
There is no diastema posterior to the superior canine, while in the latter 
genus there are two. Anterior to the canine there is a considerable one 
in the Ilyracotherium. This part is not preserved in any of the specimens 
of 8. tapirinum. The characters mentioned have induced me to separate 
the latter as type of a distinct genus, 8ystemodon. An examination of the 
figures and descriptions given by Dr. Lemoine of his Pachynolophus 
gaudryi found by him in the neighborhood of Reims, shows that it belongs 
to the genus Ilyracotherium. It is therefore distinct from either of the 
species of Systemodon, and is to be compared with the II. craspedotum of 
the Wind River country, with which it agrees in size. 
Systemodon semiiiians, sp. nov. 
This species was also abundant in the Big-Horn region, jaws and teeth 
of sixteen individuals having been obtained. Its dimensions are a little 
smaller than those of the 8. tapirinus, especially as to the premolar teeth. 
There is also a short postcanine diastema, which is not seen in the 8. 
tapirinus. 
The proportions of the maxillary series are represented by a left max- 
illary and premaxillary bone, with all 'the teeth in place, but the crowns 
lost from the first premolar anteriorly. The crowns of the true molars are 
somewhat worn, so I confine the description of these to the premolars. 
The third and fourth have considerable transverse extent, the latter being 
wider than long. The second has scarcely any internal tubercle, but 
only a low postero-internal heel. The internal tubercle of this tooth 
is large in S. tapirinus. The crown has two cusps, the posterior lower. 
The last two premolars have two external cusps close together. They 
have also an anterior external cingular lobe, as in the true molars. 
There is a posterior external basal lobe in the third premolar, but none 
or a rudiment on the fourth. No internal cingulum on the premolars. 
The superior true molars, although worn, show a prominent anterior 
external basal lobe, and no complete internal cingulum The base of the 
crown of the first premolar is narrow antero-posteriorly, and it has two 
roots as in 8. tapirinus. It is in close contact with the second premolar, 
and is separated from the base of the canine by a space a little less than 
its own anteroposteriot diameter, and less than the diameter of the 
canine. The base of the crown of the latter shows that it is not a large 
tooth, and has a wide lenticular section. The base of the external incisor 
is rather large, and is compressed. 
Measurements of superior teeth.. 
M. 
Total length of superior series * 0720 
“ “ ■“ molar “ 0310 
“ “ “premolar “ % 0250 
anteroposterior 0055 
transverse 0040 
Diameters base of canine 1881.] 
185 
[Cope. 
Measurements of superior teeth. 
M. 
Length of base of P-m. 1 0040 
Diameters P-m. Ill 
anteroposterior 0070 
transverse 0078 
anteroposterior 0070 
transvei’se 0090 
Diameters P-m. IV 
Diameters M. Ill 
anteroposterior 0100 
transverse 0125 
Some superior molars in better condition than those last described, ex- 
hibit the following characters. The intermediate tubercles are fused with 
the internal, forming a continuous cross crest, but their apices are dis- 
tinguishable. The external cusps are subconical and are wrell separated. 
The anterior and posterior cingula are strong, the external is weaker, and 
it is wanting from the posterior part of the int ernal base of the crown. 
A portion of a mandibular ramus, supporting six molars, presents the 
following characters. The teeth are a little smaller than those of S. 
tapirinus, the reduction being especially visible in the premolars. The 
cones of the crowns are more distinctly separated by notches than in that 
species, and are quite distinctly conic. The anterior ledge of the true 
molars is distinct, and there is a median posterior tubercle of the first two, 
which is represented by the wide crenate-edged heel of the third true 
molar. The anterior-internal cusps of the last two molars is double or 
bilobed ; that of the first is last. The anterior cones ot the fourth pre- 
molar are subequal, and the posterior external cone is elevated. There is 
a trace of the posterior internal. There is also an anterior ledge. The 
heel of the third premolar rises to a median blade and posterior cusp. 
The anterior cusp is elevated and compressed, and supports a small in- 
ternal lateral cusp. The base of the crown of the third premolar is 
elongate. All the teeth are rather compressed, and there is only a 
trace of an external cingulum. 
The ramus is compressed and moderately deep. The dental foramen 
is large, and its superior border is on a level with the posterior base of the 
crown of the third true molar. Its inferior base is in line with the base of 
the crown of the second true molar. 
Measurements of mandible.. 
M. 
Length of last six molars 0530 
“ true molars 0310 
Diameters third premolar 
anteroposterior 0065 
transverse 0040 
vertical 0052 
anteroposterior 0092 
transverse 0060 
vertical 0062 
Diameters second true.molar 
Diameters third true molars 
anteroposterior 0120 
transverse 0060 
Depth of ramus at P-m. Ill 0170 
Depth of ramus at front of M. Ill 0220 Cope.] 
186 
[Dec. 10, 
The nearest ally of this species outside of the genus Systemodon is prob- 
ably the Hyracotherium craspedotum Cope. This species was brought 
from the Wind River bad lands, and does not occur in the Big-Horn col- 
lection. It is about the size of the S. semihians, but is a true Hyracotheri- 
um, with a diastema behind the first premolar. The strong cingulum 
which characterizes it is not found in the S. semihians, and the inferior 
molars are wider and more robust. 
Hyracotherium craspedotum Cope. 
Bulletin U. S. Geol. Survey, Terrs., 1881, p. 199. American Natural- 
ist, 1880, 747. 
The dentition of this species is in its dimensions and proportions inter- 
mediate between the two species of Systemodon. Its three premolars 
equal four of those of the S. semihians, while the molars of the two 
species are about equal. 
A specimen having the proportions of the H. craspedotum was found by 
Mr. Wortman on the Big-Horn, but unfortunately it does not exhibit the 
characteristic cingula of the two dental sories. The second superior pre- 
molar, like that of Systemodon semihians has no internal tubercle. It is 
not certain whether there is any diastema posterior to the first superior pre- 
molar. I therefore cannot yet ascertain whether this specimen represents 
an undescribed species of Systemodon or Hyracotherium, or a strong variety 
of the II. craspedotum. The accompanying inferior true molars are inter- 
mediate in size between those of the latter species and the H. vasacciense. 
Hyracotherium vasacciense Cope. 
This species differs from the II. venticolum in its deep mandibular ramus. 
A single specimen from the Big-Horn presents the same proportions. The 
posterior inferior molar is rather short. 
Hyracotherium venticolum Cope. 
Bulletin U. S. Geol. Survey, Terrs., 1881, 198. 
Fifteen individuals of this species are included in the collections. 
Hyracotherium angustidens Cope. 
This was a very abundant species. Mr. Wortman’s collection contains 
jaws and teeth of twenty individuals sufficiently well preserved for 
identification, and a large number of other pieces of jaws, etc., which may 
be reasonably inferred to belong here. 
In my report on the Wind River collection*, I noticed three varieties of 
this species, which differ in the depths of the ramus at the line of junction 
of the fourth and fifth molars. The numbers are 12, 14, and 15.5 mm. 
respectively. The lengths of the first true molar also vary from 7 to 6.5 
and 7.5 mm. respectively. The last true molar measures in all 10.0 mm. 
The majority of the Big-Horn specimens agree with the second variety, 
but two others occur, one a little smaller, and the other a little larger 
than the average. The former measures ; length of last molar .0090 ; of 
* Bulletin U. S. Geol. Survey Terrs. V 1,1881, p. 198. 1881.] 
187 
[Cope. 
first molar .0067 ; depth of ramus at M. I, .0120. The dimensions of the 
larger variety are : length of M. iii, .110 ; of M. i, .0067 ; depth ramus 
.0165. The New Mexican forms originally described, exhibit combinations 
of several of these measurements. 
Pachynolophus ventorum Cope. 
Bulletin U. S. Geol. Surv. Terrs., 1881, p. 197. American Naturalist, 
1880, p. 747. 
One mandibular ramus. 
Pachynolophus posticus, sp. nov. 
Both rami of a mandible represent this large species. They are somewhat 
injured, and the crowns of five of the molars only can be distinctly seen. 
The latter display the characters seen in the P. ventorum and other species 
of the genus. The transverse crests are well characterized, and the valley 
between them uninterrupted. They are closed at the inner extremity by 
a low ridge nearly at right-angles with the cross crest posterior to them, 
as in the species of Rhinocerus. The anterior of these bounds an anterior 
ledge, which is quite large on the last true molar. The latter has a rather 
narrow, but prominent heel, which rises posteriorly. The fourth premolar 
has an anterior ledge, and wide heel with a diagonal crest which is median 
in front. The third premolar is similar, but smaller. The only cingulum 
is seen on the anterior part of the external side of all the true molars. 
Length of crowns of posterior six molars 0700 
“ true molars 0440 
Measurements. 
M. 
Diameters P-m. iv 
anteroposterior 0095 
transverse 0070 
Diameters M. ii 
anteroposterior 0130 
transverse 0095 
Diameters M. iii 
anteroposterior .0180 
transverse anteriorly 0092 
Depth ramus at P-m. ii 0280 
“ “ M. ii 0310 
ARTIODACTYLA. 
Miocl/Enus brachystomus, sp. nov. 
Char. gen. The typical specimen of this species is represented by all 
the molar dentition of both jaws excepting the anterior three superior pre- 
molars. It also includes pelvis, femur, the distal parts of the tibia and 
fibula, the entire tarsus and the proximal portion of the metatarsus. 
The dental characters conform precisely to those of the other species of 
Miocleenus. There is but one internal cusp of the superior true molars, 
and the intermediate tubercles are present. The fourth premolar has one 
external and one internal lobe. The inferior premolars have simple crowns 
without interior cusps or tubercles. 188 
CopeJ 
[Dec. 16, 
The characters of the tarsus are of much interest, and demonstrate that 
Mioclcenus is the oldest type of artiodactyle yet discovered, and that it is 
not altogether primitive in some of its characters. Members of this order 
have been found by Cuvier in the upper Eocene (Dichobune, Anoplotherium, 
etc.), but none have been determined as yet from the Suessonian of 
America. A species represented by teeth from the Siderolithic beds of 
Switzerland have been referred to Dichobune (G. campichii Piet.) ; 
but dental characters alone are not sufficient to distinguish that genus 
from Phenacodontidce*. Dr. Lemoine found astragali of a small Artiodactyle 
in the Suessonian of Reims, and has referred them to his supposed Suil- 
line Lophioclicerus peroni. I ha ve reported an astragalus from the Wind 
River formation of Wyoming Territory, which is almost exactly similar to 
those found by Lemoine, The specimen now described, enables me to 
characterize with some degree of completeness this interesting form, which 
precedes in time all the known American Artiodactyla. 
The characters of the tarsus are typically those of the order Artiodactyla. 
The astragalus exhibits a distal trochlea which is continuous with the 
sustentacular facet, and which articulates with both cuboid and navicular. 
♦ 
The distal portion of the fibula is free from the tibia, and its shaft becomes 
very slender. It is possible that a more perfect specimen would dis- 
play it as continuous. Its distal extremity articulates with the ascending 
tuberosity of the calcaneum. The cuboid facet of the latter is narrow. The 
cuboid and navicular bones are distinct from each other and from the 
cuneiforms. The mesocuneiform is shorter than the ectocuneiform, and 
is coossified with it. There are probably four metatarsals. The median 
pair are distinct, but appressed, their section together, sub-circUlar. The 
ateral metatarsals are slender, the external one is wanting, but its facet 
on the cuboid bone is very small. 
These characters are in general similar to those of the genus Dichobune, 
but Cuvier f does not state whether the cuneiforms are cobssified in that 
genus or not. They are united in Anoplotherium. \ Mioclcenus differs 
from Dichobune in the presence of but one internal tubercle of the superior 
molars, and in the single external tubercle of the superior premolars. Both 
genera are referable to a family to be distinguished from the Anoplotheriidce 
by the presence of the external digits. This has been already named by 
Gill the Dichobunidce. 
Char, specif. The bones are about two thirds the size of those of the 
Javan musk deer (Tragulus javanicus). The transverse extent of the 
superior true molars is greater than the anteroposterior. The composition 
of the last molar is like that of the others. The external tubercles are 
lenticular in section and the emargination which separates them is ap- 
parent on the external face of the crown. The intermediate tubercles are 
small, and are entirely distinct from the large external tubercle. There 
* See American Katuralist, 1881, December, 
f Ossemens Fossiles, v, p. 183. 
}Gaudry Enchainements d. Regne Animal, p. 147. 1881.] 
189 
[Cope. 
is a distinct cingulum which is only wanting from the inner base of the 
crown. The fourth superior premolar has a trilobate outline of the base 
of the crown, the base of the inner lobe being contracted where it joins 
the external part of the crown. The internal tubercle is conic, with a 
prolongation outwards and forwards. Intermediate tubercle not distinct. 
External, anterior, and posterior cingula. 
In the inferior true molars the external tubercles wear into crescents, 
The crowns increase in size posteriorly, which is the reverse of the order 
of enlargement in some of the other species of the genus. The fifth 
tubercle of the last molar is rather small, but is well distinguished from 
the other cusps. The internal median cusp is small, the external median, 
large. The premolars are not so much larger than the true molars in this 
as in the typical species of the genus. The second and third are more 
elongate on the base than the fourth. The latter is also less compressed 
than those that precede it. It has a short wide heel, and a small anterior 
basal tubercle. In the second and third premolars the posterior edge of 
the principal cusp is sharp, and descends gradually to the posterior base of 
the crown. Both have small acute anterior basal tubercles. The first 
inferior premolar is one-rooted, and has a Simple crown directed some- 
what forwards. It is separated from the second by a short space. The 
teeth anterior to this point are lost. 
Measurements. 
M. 
Length posterior four superior molars 0182 
Diameters P-m. IY 
anteroposterior 0040 
transverse 0042 
Diameters M. II 
anteroposterior 0043 
transverse. 0060 
Diameters M. Ill 
anteroposterior 0040 
transverse 0060 
Length of inferior molars 0330 
“ “ premolars 0192 
“ “ P in. Ill 0055 
“ “ P-m. IY 0045 
Diameters M. I. 
anteroposterior 0040 
transverse 0083 
Diameters M. Ill 
ant eroposterior 0052 
transverse .0040 
Depth of ramus at P-m. 1 0047 
“ “ M. II 0090 
Length of astragalus 0102 
Width of trochlea behind 0048 
Diameters of cuboid 
length 0070 
width of middle 0040 
etsagicus, sp. nov. 
This, the largest species of the genus, is represented by the two rami of 190 
Cope.] 
[Dec. 16, 
a mandible of an adult animal in good preservation. In their robust 
character the premolar teeth resemble those of the M. turgidus, but are 
not relatively so large, nor is the last true molar relatively so small, as in 
that species. The heel of the third premolar is obsolete, and that of the 
fourth is a wide cingulum. Neither exhibit an anterior basal tubercle, 
and in both the principal cusp is stout. The true molars widen posterior- 
ly to the anterior part of the last molar. The latter contracts rapidly to a 
narrow heel. The tubercles are all subconic, and the median ones of the 
last molar are small. There are no cingula, and the enamel is smooth. 
The ramus is not robust, and is of moderate depth. Its inferior border 
rises below the middle of the last molar tooth, and posteriorly. There is 
a “mental" foramen below the contact of the fourth premolor and first 
true molar. 
Length of bases of six posterior molars 047 
" “ three premolars 024 
“ “ P-m. II 009 
** •* P-m. IV 008 
'* " P-m. IV 005 
Measurements. 
M. 
Diameters basis of M. II 
anteroposterior 0075 
transverse 0070 
Diameter basis M. Ill 
anteroposterior 0084 
transverse 0070 
Depth of ramus at P-m. II 0080 
“ “ M. II 0140 
This species is named from the Crow Indian name of the Big-Horn 
river, Etsagie. 
The paleontologist who has examined the preceeding list, will readily 
perceive that it represents fully the Wasatacli fauna, with little admixture 
of earlier or later forms. The only genus which belongs to the Bridger or 
middle Eocene, which occurs in the Big-IIorn basin, is Pappichthys, The 
characteristic Bridger genera Ilyrachyus, Palceosyops, Uintatherium, and 
the Tillodonta, are absent, and their place is taken by Phenacodus, llyra- 
cotherium, Coryphodan and Tceniodonta, as in New Mexico. Several genera 
are, as elsewhere, common to the two horizons, and two species cannot be 
distinguished in the parts preserved. Such as Hyopsodus paulus and 
H. vicarius. A closer comparison may be made with the Wind- 
River group, on w hich I published a report in the Bulletin of the U. S. 
Geological Survey of the Territories.* The following genera found in 
that formation have not been obtained from the Big-IIorn. Protopsalis, 
Lambdatherium, Palceosyops, Ilyrachyus.\ Genera of the Big-Horn not 
obtained from the Wind-River : Cynodontomys, Anaptomorphus; Mesonyx, 
Concluding Remarks. 
*1881, Feb. p. 201. 
t Since making my report on the Wind-River fauna, I have iound the anterior 
part of the lower jaw of a species of this genus. J8S1.] 
191 
[Cope. 
Deltatherium, Oxycena; Manteodon, Ectacodon, Metalophodon; Anacodon, 
Oligotomus, Systemodon; Mioclcenus. Three of these genera have been 
found in the Bridger, and five have been obtained in the lower Eocene of 
New Mexico. Five of the genera are new to science. 
An especial feature of the Big-Horn collection, as distinguishing it from 
those brought from other regions of the Wasatch formation, is the presence 
of numerous species of Phenacodus, and of new and rare species and 
genera of Coryphodontidce. 
II. The Fauna of the Beds or Lowest Eocene of 
New Mexico. 
A number of new species and genera from this horizon were described 
in my Paleontological Bulletin No. 33. The present paper adds a few to 
this list. Up to the present time no species of Coryphodon, and but few 
specimens of Hyracotherium have been discovered in this formation, thus 
exhibiting a marked contrast to the Wasatch beds. The predominant 
genus is Catathlceus, which is represented by one very abundant species. 
The genera of Creodonta are mostty distinct from those of the Wasatch. 
The Diplarthrous Perissodactyla, so numerous in the Wasatch, are rare 
here. The genus which is ■well represented in both formations, is Phena- 
codus; and Mioclcenus occurs in both. Mesodonta are much less numerous 
than in the Wasatch, and Amblypoda have not yet certainly been found. 
This is the only Tertiary formation where the Laramie genus Champso- 
saurus occurs. It is represented by three species. 
American Naturalist, 1882, p. 156, Jan. 25th. 
An interesting new form of this sub-order has been found in the Catath- 
leeus beds (probably the Puerco formation) of New Mexico. It differs 
widely from the two genera hitherto known, Anchippodus and TUlothe- 
riurn. Owing to the absence of the superior dental series, it is not possible 
to be sure which is the canine. The inferior dental formula may be there- 
fore written, I. 2 ; C. 1 ; P-m. 3 ; M. 3; or I. 8; C. 0; P-m. 3 ; M. 3 ; or 
I. 3 ; C. 1; P-m. 2 ; M. 3. The first and second incisors are large and 
rodent-like, growing from persistent pulps ; the second are the larger. 
The third, or canines, are small and probably not gliriform. There is 
no diastema. The first premolar (or canine) has a compressed crown 
with two cusps placed transversely to the jaw axis, and has a complete 
enamel sheath, and probably two roots. The succeeding tooth is also 
transverse, and is two-rooted, judging from the alveolus. The first and 
second true molars are rooted, and the crown consists of two transverse 
separated crests, each partially divided into two tubercles. On wearing, 
the grinding surface of each assumes the form of a letter B with the con- 
vexities anterior. The last inferior molar is injured.' The rami are short, 
and the symphysis deep and recurved. 
Specific characters. The base of the coronoid process is opposite the 
junction of the second and third true molars. The ramus is deep and mod- 
PSITTACOTHERIUM MULTIFKAGUM Cope. Cope. | 
192 
tDec. 18, 
erately stout. The enamel of the first incisor does not extend below the 
alveolar border, at the internal and external faces, and does not reach it at 
the sides. It has a few wrinkles on the anterior face. The anterior enamel 
face of the second incisor is thrown into shallow longitudinal grooves with 
more or less numerous irregularities from the low dividing ridges. There 
is a deeper groove on each side of the tooth, and there are about a dozen 
ridges between these on the anterior face. Both cusps of the first pre- 
molar are conic, and the external is the larger. The second true molar 
is a little smaller than the first. The enamel of the premolars and molars 
is smooth, and there are no cingula. 
Probable length of dental series, .0750; diameters of I. i: anteropos- 
terior, .0120, transverse, .0060; diameters I. 2; anteroposterior, .0160, 
transverse, ..0115 ; diameters P-m. i; anteroposterior, .0072 ; transverse, 
.0130; diameters of M. ii. anteroposterior, .0090, transverse, .0090. 
Length of true molars, .0038 ; depth of ramus at M. ii, .0360. 
The short deep jaws of this animal must have given it a very peculiar 
appearance, not unlike that of a parrot in outline. 
PsiTTACOTHEBIUM Sp. hOV. 
Represented by two mandibular rami of two individuals, one adult, the 
other nearly so, but with the last inferior molar not fully protruded. The 
latter specimen must be used for description, as it presents two molar 
teeth, while the other specimen has lost them. 
The most obvious difference from the P. multifragum is its inferior size, 
which can be readily perceived from the measurements given. The pos- 
terior crest of the molars appears to have less transverse extent than in 
the larger species. This crest in the last inferior molar has a curved 
crenate edge, with a small conic tubercle at its external extremity. The 
anterior crest consists of two conic tubercles, whose apices converge, but 
whose bases are closely appressed, and only distinguished by a superficial 
fissure. The valley between the crests is uninterrupted. The preceding 
molar is larger, and its posterior crest is like that of the lost molar. The 
apex of the anterior crest is broken off. 
The ramus deepens rapidly forwards, and contains the enormous alve- 
olus for the incisors. The coronoid process leaves the alveolar border at 
the line separating the last two molars, or, in the smaller specimen, a 
little anterior to this point, and is quite prominent. The masseteric fossa 
is well marked, but shallows gradually anteriorly and inferiorly. 
Measurements. 
M. 
Depth of ramus at penultimate molar. 027 
Width of last molar anteriorly 008 
Length of crown of do 009 
No. 1. 
Depth of ramus of penultimate molar 029 
“ “ at P-m. ii 043 
Length of five consecutive alveoli 047 
From the Puerco bed of N. W. New Mexico. 
No. 2. 1881.] 
193 
[Cope. 
TrIISODON HEtLPRINIANTJS, Sp. nOV. 
This species may be readily recognized as smaller than the T. quiviren- 
sis, and as having the anterior inner cusp of the inferior true molar of 
larger proportions than in the corresponding teeth of the latter species. 
It is only represented in my collection by a portion of a lower jaw, which 
supports only one well preserved molar. As the fourth premolar is not 
present, it is not positively ascertained that the species does not belong to 
Ictops. 
The anterior cusp is very low, and is nearer the inside than the middle 
of the anterior border. The principal anterior cusps are opposite, and the 
external is a little the larger. The heel is larger than the basis of the an- 
terior cusps, and has convex borders. Its internal border supports three 
tubercles, and the external border rises into a cutting lobe with lenticular 
section. Enamel smooth. No cingula, but the external base is injured. 
Measurements. 
M. 
vertical 
of cusps .0070 
of heel 0052 
Diameters of inferior molar 
anteroposterior 0110 
transverse 0065 
Puerco beds of New Mexico. 
Dedicated to my friend, Professer Angelo Heilprin, of Philadelphia. 
Sarcothraustes antiquus, gen. et sp. nov. 
Char. gen. We have in evidence of the characters of this genus, the 
last two superior molars, the last one lacking the crown; and parts of 
both mandibular rami, which exhibit teeth as far posteriorly as the first 
true molar inclusive ; all belonging to one individual. A part of a skele- 
ton of a second individual, which includes a fragment of lower jaw, be- 
longs probably to this species. 
Sarcothraustes resembles both Amblyctonus and Mesonyx, but it is prob- 
ably to the latter genus that it is allied. The last superior molar is trans- 
verse, much as in Oxyama. The crown of the penultimate is-subtriangular 
and transverse. It has two external subconic cusps and a single internal 
lobe, whose section on wearing is a V, each branch of the face extending 
to the base of the corresponding external tubercle. There are three small 
inferior incisors, and a large canine. There are probably only three in- 
ferior premolars, the first one-rooted. The crown of the second has no 
heel. The crown of the third has a short wide heel. The crown of the 
first true molar consists of an anterior elevated cone and a posterior heel. 
The latter is wide, having a posterior transverse, as well as a longitudinal 
median keel. The fragments of the supposed second individual include 
two large glenoid cavities with strong preglenoid crests, as in Mesonyx. 
As compared with Mesonyx, this genus differs in the Y-shaped crest of 
the penultimate superior molar ; in Mesonyx it is represented by a simple 
cone. The last superior molar of Mesonyx is triangular and not transverse, 
but the composition of the crown of that tooth in Sarcothraustes must be Cope.] 
194 
[Dec. 16, 
known before the value of this character can be ascertained. If the view 
that Sarcothraustes has but three inferior premolars be correct, this charac- 
ter distinguishes it from Mesonyx, as do also the transversely expanded 
heels of the molars. The family Mesonyehidcs may be for the present re- 
garded as embracing the three genera of Sarcothraustes, Mesonyx and 
Dissacus. * 
Char. Specif. The penultimate superior molar has a strong posterior 
cingulum which commences within the line of the internal bases of the 
external cusps, and rises into considerable importance behind the internal 
cusp. There is also an anterior cingulum which does not rise internally, 
and which is continuous with a strong external basal cingulum. The 
latter passes round the posterior base of the posterior cone, and runs into 
the posterior branch of the internal Y. The posterior cone is smaller than 
the anterior cone, and its apex is well separated from the latter. The ap- 
pearance of this tooth is something like that of a carnivorous marsupial. 
The symphysis mandibuli slopes obliquely forwards, and is united by 
coarse suture. The ramus is stout and deep, as compared with the size of 
the molar teeth. The roots of the teeth are relatively large, especially 
those of the first two premolars. The crown of the canine is lost. The 
first premolar points forwards, nearly parallel with the canine, and diver- 
gent from the second premolar. The crown of the second premolar is 
small and subconic, and has a rudimental heel, and no anterior basal tuber- 
cle. The first true molar resembles considerably that of Mesonyx. There 
is a small anterior basal tubercle on the inner side of the principal cusp. 
The expansion of the heel is transverse only, there being no longitudinal 
lateral edges or tubercles. The enamel is obsoletely, rather coarsely 
wrinkled. There are two rather large mental foramina ; the posterior be- 
low the anterior root of the first true molar, and the anterior below the 
posterior root of the second premolar. 
Measurements. 
M. 
Diameters of superior M. ii 
anteroposterior externally .015 
transverse 024 
Anteroposterior diameter of base of M. .iii 0095 
Anteroposterior diameter base of crown of inferior 
canine 020 
Length of bases of three inferior premolars 038 
anteroposterior 019 
transverse 0095 
vertical 0110 
Diameters inferior M. i. 
Depth of ramus at P-m. iii 0520 
Width “ “ 022 
* American Naturalist, Dec., 1881. 1881.] 
195 
[Cope. 
Champsosaurus puekcensis, sp. nov. 
I have already announced the discovery * of this Laramie genus in the 
Puerco beds of New Mexico, and described a species, C. australis, from 
that region. I now introduce two additional species from the same hori- 
zon. One of these is represented by a number of fragments which include 
three dorsal and four caudal vertebrae of apparently one individual. They 
represent an animal of larger size than any of those heretofore referred to 
Champsosaurus, excepting the C. vaccinsulensis. In all of the vertebrae 
the neural arch is more or less coossified with the centrum, and the animal 
had probably reached its full size. 
One of the dorsal centra is split vertically and longitudinally, and shows 
the structure already figured by Leidy in the Ischyrosaurus antiquus f 
Leidy. The surface exposed displays two diagonal lines of fissure cross- 
ing each other at right angles. They indicate clearly the mode of origin 
of this ampliiplatyan type of centrum. The centrum is first deeply am- 
pliicoelous as in the Theromorplious reptiles of the Permian. The conical 
cavities are filled by the ossification of the remaining portions of the noto- 
chord, forming a conical body which always remains distinct from the re- 
mainder of the centrum. 
The articular faces of the dorsal centra are a little wider than deep, and 
the depth about equals the length of the body. They are not nearly so 
depressed as those of C. australis, and their outline is different. This is 
wider above and narrows below ; in both C. australis and C. saponensis the 
inferior outline is part of a circle. None of the dorsals preserved are 
keeled below. There is a fossa below the diapophysis which has a subver- 
tical posterior boundary. The general surface (somewhat worn) does not 
display wrinkles near the articular faces. An anterior dorsal has a short 
compressed diapopliysis with a narrow figure 8 articular surface, and its 
superior border is in line with the roof of the neural canal. The anterior 
caudals have subround articular faces ; the posterior are more oval and 
the bodies compressed. With greater compression, the length increases. 
Measurements. 
anteroposterior 025 
vertical 025 
transverse 080 
M. 
Diameters of an anterior dorsal 
Height of costal facet of do 021 
Diameters neural canal do. 
vertical 007 
transverse 009 
Diameters anterior caudal 
anteroposterior 024 
vertical 021 
transverse 021 
anteroposterior 025 
vertical 018 
transverse 018 
Diameters posterior caudals 
* American Naturalist, 1881. p. 669. 
t Transac. Amer. Philos. Soc. 1860. Cope.] 
196 
[Dec. 16, 
The typical specimen was found by Wm. Baldwin near the Puerco 
river, west of the Nacimiento mountain, New Mexico, in the typical 
locality of the Puerco formation. 
Champsosaurus saponensis, sp. nov. 
Represented in my collection by six cervical and several dorsal vertebrae, 
one only of the latter with well preserved centrum, parts of ribs, and 
various other bones, whose reference is not yet certain. 
The cervical vertebrae include the os dentatum or centrum of the atlas. 
This shows its streptostylicate character in its distinctness from both the 
centrum and the free liypapophysis of the axis. Nevertheless it is more 
Crocodilian than Lacertilian in form. Jts anterior face is transverse, with 
a little lip carrying forwards the floor of the neural canal, below which the 
face is leveled posteriorly. The inferior surface is narrow and transverse, 
as though adapted for the anterior part of the liypapophysis of the axis. 
At each side it terminates in a prominent tuberosity, as though for the 
attachment of a cervical rib as in the Crocodilia. The anterior face is 
bounded posteriorly by a transverse groove which terminates in a fossa 
on each side. The posterior articular face of the os dentatum is wider 
than deep. The lateral angles of the superior face are rounded, and its 
median portion is concave. 
The axis displays a large facet for the liypapophysis. Behind it the 
inferior middle line is not keeled, but is coarsely wrinkled longitudinally. 
The posterior edge of the hypapopliysial facet is the most prominent part 
of the inferior surface. The posterior articular face is deeper than wide. 
This is true of the faces of all the cervical vertebrae. The latter gradually 
increase in size posteriorly, and the dorsals become larger. The articular 
faces of all the centra are regularly rounded and not contracted below. 
The five cervicals are strongly keeled below ; the keel of the third centrum 
being split up anteriorly into narrow ridges. On the sixth the keel is 
more prominent and acute. The dorsal is not keeled. A trace of the 
parapophysis appears low down on the fourth cervical; it rises and 
becomes prominent as a round tuberosity on the fifth and sixth. It ap- 
pears on the superior edge of the centrum of the dorsal vertebra, where 
it is connected with the diapophysis. It is near the middle of the length 
of the centrum, and not near the anterior border as in C. australis. 
The surfaces of the vertebrae are very smooth excepting where thrown 
into coarse wrinkles near the borders of the articular faces and near the 
liypapophysis. The edges of the articular faces are somewhat revolute 
on the sides in the cervicals, but not on the dorsal. They are impressed 
in the centre to a point, most strongly so as we pass forwards in the 
series. There is a fossa below the space anterior to the parapophysis of 
the dorsal vertebra, which is abruptly bounded below by a horizontal 
angle. A separate neural spine perhaps of a cervical vertebra, has the 
following form. It is stout, and is contracted rather abruptly at the apex 
from behind forwards. The section is broadly lenticular, angulate in 1881.] 
197 
[Cope 
front, and truncate behind. The posterior face has several longitudinal 
wrinkles, including a median raised line, and there are some more irregu- 
lar wrinkles on the sides. 
Measurements of vertebra. 
M. 
Anterior face of os dentatum 
width 025 
depth (oblique) 012 
Posterior face of os dentatum 
width 020 
depth 018 
Length os dentatum above 014 
Diameters axis 
posterior face 
depth 022 
width 020 
Hypapopliysial facet os dentatum 
length 0185 
deplh 008 
width 014 
length 022 
Diameters fourth cervical 
anterior 
depth 0225 
width 022 
Diameters sixth cervical 
length 0215 
anterior 
depth 0245 
width 0235 
Spaces between parapophysis and diapopliysis of do 0040 
length 0265 
Diameters of dorsal 
anterior 
depth 0200 
width 0265 
Height of neural spine of'?, from postzygapophysis 0210 
Anteroposterior width of do. at base 0100 
The portions of ribs are separated heads and shafts. The former are 
double and therefore cervical, and are quite large. If the shafts belong to 
them, the neck of this species must have been wide. The shafts are slender 
and are of dense bone. The section is oval at the middle, but towards 
the distal extremity becomes flattened and grooved and delicately line 
ridged on one side. The extremities of the long bones are without con- 
dyles but have concave surfaces like those of the ribs. The bodies are ro- 
bust and angular. They may be abdominal ribs of unusual stoutness. 
From the Puereo beds, I). Baldwin. 
Published February 20th, 1882.