HISTORY OF THE ARTIODACTYLA 



401 



tion in the number of digits from the original five, the same 

 reduction of the ulna and its coalescence with the radius and 

 the loss of the fibula save for its two ends. There was also a 



MM JF M W M 



Fig. 214. — Right pas of camels. A, ^Protylopus. B, ^Poebrolherium. 

 C, iProcamelus. (After Cope.) D, Guanaco. 



similar development of the high-crowned, or hypsodont, grind- 

 ing teeth, from the low-crowned, or brachyodont, type. In 

 still another respect there was a similarity in the mode of de- 

 velopment of the two families, namely, in the way in which 

 the several phyla of each originated. For the earlier portion 

 of their history there was in each but a single distinguishable 

 2d 



