420 LAND MAMMALS IN THE WESTERN HEMISPHERE 



They differ further in the character of the hair, which is short 

 and woolly on the body and hind quarters, very long and shaggy 

 on the head and neck. In the Pleistocene of North America 

 there were at least seven recognizable species of bisons, which 

 ranged over the continent from Alaska to Florida, though it 

 is not probable that they were all contemporary. One of the 

 earliest and by far the largest of these was the gigantic B. 

 '\latifrons, a specimen of which in the American Museum of 

 Natural History measures six feet across the horns in a straight 

 line ; this was a Mississippi Valley species and extended from 

 Ohio to the Gulf of Mexico and westward to Kansas and Texas. 

 Another gigantic species (B. ]crassicornis) lived in Alaska in 

 association with a second and smaller species {B. ]occidentalis) 

 which ranged as far south as Kansas. B. \occidentalis, though 

 smaller than the preceding species, was larger than the existing 

 one and was remarkable for the great size of the hump. The 

 bisons were migrants from the Old World and are the only 

 members of the great ox-tribe that ever reached America. At 

 present the Old World has but a single species of Bison {B. 

 bonasus), which has been saved from extermination only by the 

 most rigid protection. 



Neither sheep nor bison extended their range to South 

 America ; both are and have been essentially northern groups 

 and seem to have been unable to cross the tropics. 



From the foregoing account, confused as it unavoidably is, 

 one thing at least stands out clearly, that North America 

 played a very insignificant r61e in the evolution of the Pecora, 

 and has only two peculiar groups, the Prong Buck and the 

 American types of deer, and of these, the probable American 

 ancestry does not extend back of the lower Miocene and per- 

 haps not so far. Even in the Old World the story, so far as it 

 has been deciphered, is by no means clear and consistent, which 

 is no doubt due to the fact that the regions from which Tertiary 

 mammals have been obtained are so small in comparison with 



