PHENACODUS. 



331 



of its digits had three phalanges. As I am considering the 

 genealogy only of hoof-bearing animals, I shall not go fur- 



FiG. 197. — Fore Foot of 

 Rhinoceros (ith real length). 



Fig. 198. — {After Caud/y.) Left 

 Front Foot of Acerotheriu.m 

 Tetradactylum (ith real length). 



ther back than the Phenacodus. Having now arrived at an 

 animal with five toes, I may point out that in no case do 

 the digits of any normal mammal (an animal which suckles its 



