Jan, 18, 1884] 503 [Cope, 
Synopsis of the Species of Oreodontide. By H. D. Cope. 
(Read before the American Philosophical Society, January 18, 1884.) 
The tribe Ruminantia first appears in the White River Miocene period 
in North American geological listory. It is represented there by a num- 
ber of genera, which pertain to several family types. The most aberrant 
of these, the Oreodontida, includes the largest number of forms, generic and 
specific. The Poébrothertide certainly embraces but few species, while 
a third group of genera, represented by Leptomeryx, which are inter- 
mediate between the Tragulina and Pecora, and should be perhaps regard- 
edas aberrant Zragulida, also includes a small number of species. 
The Oreodontide constitute a family related to the Anoplotheriida of 
the later Eocene, but representing a more specialized condition of the 
structure of the molar teeth, in the full development of the selenodont 
type, which is rudimental in the Anoplothertide. Their feet, on the other 
hand, are less specialized than in the latter family. Asa family, the Oreo- 
dontide display very little tendency in their limbs to the specialized con- 
dition of the Ruminantia, but are more like those of the suilline groups, 
und, among recent families, of the Zippopotamida. 
OREODONTID ©, 
Dentition ; superior mcisors present; molars selenodont. Cervicals 
with the transverse processes perforated by the vertebrarterial canal. No 
alisphenoid canal. Ulna and radius, and tibia and fibula distinct. Meta- 
podial bones four on each foot, with incomplete distal troch}gar keels. 
Lunar bone not supported by magnum, Navicular and cuboid bones dis- 
tinct. 
The preceding synopsis of its characters should furnish a basis for the 
definite location of the Oreodontide in the system. Dr, Leidy called its 
species Ruminating hogs, and created a family for Oreodon and the allied 
genera, under the name of Oreodontide. 'This family is adopted by Prof. 
Gill who includes in it the Agriochoeride of Leidy, and places it in his 
division Pecora, which is more comprehensive than the Pecora of Prof. 
Flower, being nearly identical with the Selenodonta of Kowalevsky. 
More precise expression of its affinity to the existing families is not given, 
excepting to place it under a division ‘‘incertx sedis.’’ 
As a selenodont type, this family is excluded from the Artiodactyla 
omnivora, and as having its metapodial bones distinct, it cannot be placed 
in any recent family excepting the Zragulidw. From this family it is 
distinguished by the distinct ulna and radius. We then turn to the ex- 
tinct families Poébrotheriidw and Anoplotheriidw. The former agrees 
with the Zragulide excepting in its Cameloid cervical vertebra, 
while the latter differs from the Oreodontidw in the structure of 
the feet, The <Anoplotheriidw are didactyle in front, and tridactyle 
behind. The posterior foot has a well-developed second digit directed 
PROC. AMER. PHILOS, 800, XxT. 116 8L. PRINTED JUNE 6, 1884. 
