414 ZOOLOGY 



in Europe. In both cases the inter- 

 vention of man has been necessary to 

 preserve the animal from complete 

 extinction at the hands of man himself. 

 The mountain sheep of our Western 

 states are true sheep (Ovis), and are 

 closely allied to others found in Asia 

 and the region of the Mediterranean. 

 The true goats (Capra) belong to the 

 Old World ; the Rocky Mountain goat 

 is quite different, and is more nearly 

 related to the chamois of European 

 mountains. 



(h) Peris sodactyla. Odd-toed ungulates, including 

 the horses, tapirs, and rhinoceroses. The 

 rhinoceros group, now confined to the Ethio- 

 pian and Oriental regions, was once richly 

 represented in America. 

 (i) Proboscidea. Elephants, including mastodons 



and mammoths. 



(/) Sirenia, which are aquatic derivatives of the 

 ungulate type, as the seals are of the carniv- 

 orous group. The living forms are the mana- 

 tee and dugong. 

 Whales (k) Odoritoceti, or toothed whales, including dolphins 



and porpoises. 



(/) Mystacoceti, the whalebone whales. 

 The arrangement of the orders of mammals, as here 

 given, does not represent the course of evolution in any 

 accurate way, nor is it possible to do so in a single series. 

 The evolution of the. mammals has been treelike or 

 fanlike, the several orders diverging along their own 

 paths, and not as a rule giving rise to any other. This 

 can be readily demonstrated by a study of the struc- 



