254 
PERISSODAOTYLA. 
the impression that the fore limb is lighter than the hinder; it displays a 
quite small face of contact with the ulna. The olecranon is much com¬ 
pressed. 
The femur is moderately stout, and the trochlear groove for the patella 
is elevated, with the bounding crests subequal. The inner condyle is a little 
more produced than the outer. The external or third trochanter is well 
developed, as are the great and small trochanters. The distal end of the 
tibia has the usual Perissodactyle structure. It presents a well-marked inner 
astragalar groove, and the inner half of the still deeper external groove, 
which was completed by the lost fibula. The three angular tuberosities, 
external, anterior, and posterior, are well marked; on the inner side of the 
end of the tibia, just in front of the external tuberosity, there is a marked 
tendinous groove. The calcaneum has lost its cuboid facet, but the 
remainder of it nearly resembles the corresponding parts in the Tapir. The 
free shaft is rather elongated and compressed, and is not flattened on the 
inferior face. The inner superior facet stands on a transverse tuberosity, 
while the front of the tuberosity, which was applied to the astragalus behind, 
supports a facet. 
The general structure is Tapiroid. The number of digits remains 
unknown. 
Of the three species known to me, two are about the size of the Ked 
Fox, while the third, Orotherium loevii, is smaller. 
> 
Orotherium cristonense, Cope. 
Plate Ixv, figs. 13-14. 
OroMppus major, Marsli, Cope, System. Cat. Vert. Eocene New Mexico, U. S. Geog. 
Survs. W. of 100th M., 1875, pp. 20-21. 
Both mandibular rami nearly complete, from the posterior end of the 
last molar to the end of the symphysis, represent this species. The portion 
of the jaw supporting the molars is of moderate stoutness, but the ramus 
contracts vertically in front of the second premolar, and is moderately 
concave transversely between the first premolar and the canine. The 
symphysis is shallow and posteriorly horizontal; its length is equal to that 
of the three true molars. 
