Mammalia: Classification 757 



dary with one hump, and the two-humped bactrian — of Asia and 

 Africa; llamas of South America (Fig. 571). 



TRAGULINA: 



Tragulidae: The "mouse deer" or chevrotain (Tragulus) of 

 Asia and Africa; smallest of ungulates, standing about 12 inches high. 

 Deerlike in appearance, but without antlers (Fig. 566). 



PECORA: 



Cervidae: The deer tribe. Head usually bears a pair of antlers 

 developed as solid bony outgrowths (covered temporarily by skin) 

 from the frontal bones and more or less elaborately branched ; shed and 

 regenerated annually. Antlers usually present in male only, but in a 

 few cases (e.g., reindeer) in both sexes; entirely absent in musk deer. 

 Deers (Cervus: Fig. 572), elk, moose, reindeer. 



Giraffidae: Extremely long legs and neck, adapted to feeding on 

 foliage of trees. The "horns" are a pair of short frontal bony knobs, 

 permanently covered by hairy skin. Giraffe (Fig. 194) and okapi, 

 African only. The okapi (Fig. 573), in size and in the conspicuous 

 stripes on the legs, resembles a zebra, but it is artiodactyl and other- 

 wise giraffe-like, but with relatively shorter legs and neck. It was un- 

 known (i.e., to white men) until 1900, when it was discovered in the 

 Belgian Congo. 



Antilocapridae : The prongbuck or "American antelope" 

 (Antilocapra). The single-pronged frontal horns have a permanent 

 bony core but its horny covering is shed annually. 



Bovidae: "Hollow-horned," but the "hollow" of the horny struc- 

 ture is filled by a permanent bony core produced by the frontal bone, 

 and the horn is never shed. Horns usually present in both sexes. An 

 Asiatic antelope has two pairs of horns, both borne by the frontal 

 bones. Cattle (Bos), bison, sheep (Ovis), goat (Capra), antelopes 

 (Fig. 574), gnu, chamois, gazelle. 



Distribution of Artiodactyla. The Artiodactyla, taking the 

 Order as a whole, are extensively represented in both Eastern and 

 Western Hemispheres, but totally absent from the regions of Australia, 

 New Zealand, and Polynesia except as introduced by man. Wild pigs 

 occur only in the Eastern Hemisphere, peccaries only in the West cm 

 Hemisphere. The hippopotamus is African only. Cervidae are numer- 

 ous in both hemispheres, mostly in their more northern parts. Ante- 

 lopes (of Bovidae) are in the Eastern Hemisphere only; the prongbuck 

 ("American antelope") is found only in western North America. 



Order 15: PROBOSCIDEA. Elephants, largest existing land 

 mammals. In contrast to perissodactyl and artiodactyl ungulates, in 

 which there is a strong tendency to concentrate the function of the foot 



