674 AFRICAN GAME ANIMALS 



enamel, dentine, and cement, which form a perfect grinding 

 surface. The great length of the crown gives the teeth a long 

 period of wear. The horse is in this way fitted to masticate 

 tough herbage rapidly and thoroughly and is placed at very 

 little less disadvantage than the ruminant hoofed mammals 

 which have an accessory pouch to the stomach from which 

 the food is returned to the mouth and masticated at leisure. 

 The incisor teeth are well developed in both jaws and are 

 also very long-crowned and subject to a great amount of 

 wear. The pits or "cups" in the crowns of these teeth are 

 a peculiarity found only in the horse and its fossil allies. 

 In age they disappear, but they persist for a period of 

 eight or ten years, and by their relative size in the various 

 incisor teeth the age of a horse is commonly determined by 

 horse dealers. In addition to the incisor teeth, which 

 provide the horse with a formidable biting apparatus, the 

 males are furnished with well-developed canine teeth in 

 both jaws. The females lack the canines, which are only 

 represented occasionally by vestiges beneath the gums. 



During the last geological period or Pleistocene age the 

 Equidce were a dominant type, and widely spread through 

 North and South America, Europe, Asia, and North Africa; 

 but to-day they are totally absent in a wild state from the 

 New World and occur only in a small part of the Old, 

 namely, in southern Asia and in the eastern half of the 

 African continent. The fossil species were quite numerous 

 and several distinct generic types were represented. At the 

 present time there exist a single or at most two generic 

 types, and some seven distinct species. Their extinction 

 in the New World is of such recent occurrence that it was 

 doubtless due to some insect-born infection akin to the 



