72 



KANSAS CITY REVIEW OF SCIENCE. 



end and the ulna is so intimately blended with the radius as to completely dis- 

 appear in the lower half of its extent. The internal lobes of the superior molars 

 a/and//, are connected with the cross-ridges d:^:^: and pec (Fig. 23). The only 



Fig. 18. 



S'de view of same, (after Cope). 



Fig. 19. 



Skull of Protohippiis sejunctus, (afier Cope). 





'*'i^:*^<>-'-X.V: V -i 





Fig. 20. 



Under view of same, (after Copej. 



diffe lice of generic value between Hippidium and Equus is seen in the relative 

 of the antero- and postero-internal lobes ai and pi. In Equus the anterior ai 



