Cope.J 510 [ Jan 18j 



descends to below the middle, as in Hypertragulus, and there is no verti- 

 cal nor horizontal distal crest. The inferior calcaneal facet is undivided 

 and not grooved, and does not extend over the internal border of the in- 

 ferior side of the bone. It exhibits an acute border on the external side. 

 The calcaneum is rather elongate, and the free portion is compressed and 

 "with obtuse margins above and below. The transverse astragalar pro- 

 cess is not large and is not produced beyond its facet. The ascending 

 plate is well developed and has a superior, uninterrupted convex facet for 

 the fibula, with a narrow facet on its inner side. The inner distal astraga- 

 lar facet extends the entire length of the cuboid facet. There is a longi- 

 tudinal ridge on the external side of the distal end of the calcaneum. 



The navicular and cuboid bones are distinct from each other and from 

 the ectocuneiform. The astragalar ligamentous fossa is in the naviculo- 

 cuboid suture. The inferior proximal angle of the cuboid is produced 

 posteriorly, and the peroneal process well forwards. The ectocuneiform 

 is distinct, and much wider than long. The mesocuneiform is exterio-. 

 posterior in position, and the transverse diameters are small. It is pro- 

 duced distally, overlapping the head of the second metatarsus. Ento- 

 cuneiform wanting. The metapodial bones are entirely distinct. The 

 lateral metatarsals are well developed. The second articulates with both 

 the ecto- and mesocuneiform bones, by a proximal extremity which is 

 laterally compressed. The third and fourth are subequal in width, and 

 articulate exclusively with the ectocuneiform and cuboid respectively. 

 The fifth metatarsus is compressed proximally, and the external part of 

 its extremity articulates with a lateral fossa of the cuboid. The distal 

 articular extremities of the metapodials are separated from the anterior 

 face of their shafts by a transverse groove ; and they have a well marked 

 articular fossa on each side. The trochlear tongue only exists on the 

 posterior face, where it is prominent and compressed. It disappears on 

 the middle of the distal end, and is wanting on the anterior face. The 

 phalanges are depressed proximally, the penultimate ones distally also. 

 The ungues are rather depressed and have convex external borders. There 

 is a pair of sesamoid bones below the distal articular extremity of the 

 metatarsals. 



History. The dental and cranial characters of this genus were fully 

 described by Dr. Leidy in 1852, as already cited. In the Extinct Mam- 

 malia of Dakota and Nebraska, published in 1869, Dr. Leidy added the 

 following points in the osteology of the skeleton of the Oreodontidce (p. 

 72) : " What are supposed to be the bones of the forearm and leg are 

 discrete, as in the hog, and the bones of the feet correspond in number 

 with those of this animal." In 1873* Prof. Marsh confirmed these state- 

 ments so far as regards the metacarpal bones, and added that "the navicu- 

 lar and cuboid bones were loosely coossified or separate." The structure 

 of the vertebra?, and of the greater part of the scapular and pelvic arches, 



*Amer. Journ. Sci. Arts, p. 409. 



