FOSSIL VERTEBRATES— MAMMALIA 1 75 



are deficient or entirely absent, and the upper canines are either 

 absent, small, or enlarged as in the Tragididce . The carpals and 

 the tarsals are anchylosed in some forms and the metapodials 

 are united to form a cannon bone. The whole structure of the 

 skeleton indicates the lightness and the speed of the deer tribe. 



Blastomeryx. — North America, Miocene and Pliocene. 



Paleomeryx. — Europe, Miocene. 



Helladotlierinm. — Europe and Asia, Upper Miocene. This 

 form with the Samotherium of Europe are interesting as being 

 the ancestors of the giraffe, Camelopardalis, which is found in 

 the same deposits and then disappears from the record to appear 

 again in the Recent in Africa. 



Sivatherium and Bramatherium are large forms, strikingly 

 resembling the moose, which are known from the Miocene 

 deposits of India and unknown since. 



Most of the modern forms of the family seem to have 

 appeared in the Pliocene and their remains are especially well 

 preserved in the European deposits, but not until the Pleistocene 

 time do the deposits indicate anything like the profusion of 

 numbers and the widespread distribution of the group that 

 obtains at present. 



Cavicornia. — The group is in few particulars different from 

 the Cervicornia. The horns are not deciduous or bony, they are 

 present in both sexes. The teeth are similar in many respects, 

 but the upper canine is always lacking as well as the upper 

 incisors. The metapodials are always united to form a cannon 

 bone and the lateral digits are the merest rudiments or are com- 

 pletely absent. In general the skeleton is very similar to that 

 of the preceding group, but in many of the forms it is much 

 more robust. One thing characteristic of the group is the width 

 of the brow. Where the horns are set close together in the 

 Cervicornia, in this group they are wide apart, a condition that 

 reaches its greatest development in the Bovidae, the cows and 

 buffaloes. It is of interest to note that the same loss of the 

 enamel which took place on the upper surface of the teeth of 

 the Equidae also took place in the Artiodactyla, and the later 



