Peterson: The Osteology of Promerycochcerus. 191 



montanus. The condyles are of nearly the same size, but the groove 

 separating them is narrow in P. carrikeri. The rotular trochlea has 

 the same asymmetry, which obtains in P. montanus, and is, as Scott 

 states, a distinctly modernized character, differing from what is seen 

 in earlier representatives of the family. Some species of Promeryco- 

 chcerus apparently have the groove more nearly as it is in Merycoidodon. 



31 32 



Fig. 31. Internal and posterior views of femur of Promerycochasnis carrikeri. 



No. 1081; ^ nat. size, i, internal; 2, posterior. 



Fig. 32. Anterior view of tibia and fibula of Promerycochxrus carrikeri. 



No. 1081; \ nat. size. 



Patella (Plates XXIII and XXXV).— The patella is large, very 

 convex and rugose on the anterior face, truncate above, and terminating 

 in a sharp tubercle, which is bent downward and backward. The 

 articulating surfaces for the femoral trochlea are broad, the external 

 more convex than the internal, and the median ridge is quite concave 

 from above downward. 



