418 LAND MAMMALS IN THE WESTERN HEMISPHERE 



Antelopes even penetrated to South America, and three 

 genera of them have been reported from the Pleistocene of the 

 Brazilian caverns and the Argentine pampas, but they were less 

 successful in establishing a foothold than were the deer, and form 

 no part of the modern Neotropical fauna. 



11. Bovidce. Sheep, Bisons, Oxen, etc. 



A series of genera, of disputed systematic position, is rep- 

 resented to-day by the so-called Musk-Ox (Ovibos moschatus), 

 which is now exclusively North American, but in the Pleistocene 

 ranged over northern Asia and Europe as far west as Great 

 Britain. The Musk-Ox, which is at present found only in the 

 extreme north, is a heavy, short-legged animal, three and a half 

 to four feet high, and six feet or more in length ; the body is 

 covered with a dense coat of woolly hair overlaid by a thatch of 

 long, straight hair, which gives the animal a very shaggy ap- 

 pearance. The horns are broad at the base, especially so in old 

 males, in which they meet in the middle line and cover much of 

 the head as with a horny casque ; they curve downward and then 

 upward and forward, with the tips directed toward the front ; in 

 the females and young males the horns are very much smaller. 



This series cannot be traced back of the Pleistocene, in 

 which epoch it was not only far more widely distributed, but 

 also very much more diversified, no less than three extinct 

 genera, in addition to the existing one, having been found in 

 the North American Pleistocene. One of these ( ^Symbos) , which 

 extended from Alaska to Arkansas, had horns which were 

 smaller and shorter than in the modern genus, and, even when 

 fully developed, did not meet in the middle line of the head. 

 The other two genera, from California {^Euceratherium and 

 '\Preptoceras Fig. 116, p. 203), are of great interest as showing 

 affinities to the Musk-Ox and also to sheep and to certain ante- 

 lopes, such as the Takin {Sudor cas) of northern India and Tibet. 

 They serve to connect the musk-oxen with other Cavicornia, 

 but the origin of all these animals is to be sought in Asia. 



