NATUEAL HISTORY OF THE OX. 15 



and in fact all Kuminants, in course of time have their molars 

 ground down so as to hecorae lunate-shaped. 



With regard to the omnivorous and non-ruminating ani- 

 mals, as we have shown above, the pig is included among them. 

 The teeth of this animal are suited to the mastication of many 

 kinds of food. The canine teeth are very prominent, and in the 

 male they project considerably and are so large that they have 

 received the name of ** tusks," which in the wilder varieties are 

 formidable weapons. The stomach of a pig is not nearly so 

 complex as that of the ruminant, and but slightly more so than 

 that of the horse. The pig is possessed of four digits, two long 

 ones and two short ones on each of the four legs. The nose or 

 snout is prominent and cylindrical in form. 



The hoofed animals may have either an even number or an odd 

 number of toes. Those which have an odd number are called 

 the Perissodactyla, and they include the horse and ass, the tapir, 

 and the rhinoceros. The two genera Equus and Asinus are 

 collectively designated the Equidse or Solidungula, and the most 

 prominent feature which distinguishes them is the possession of 

 one perfect digit or finger to each leg. 



The genus Equus contains only one clearly-defined species, the 

 difi'erences in the breeds of horses being in all probability results of 

 the prolonged influence of diff'erent external circumstances, such 

 as locality, management, climate, and so forth. The stomach of 

 the horse is simple and rather small. 



The Artiodactyla are sub-divided into four sections: — 



(1) The non-ruminating Artiodactyla, or Swine, including 



the pigs, peccaries, and the hippopotamus. 



(2) The cushion-footed or Tylopoda, including the camels 



and llamas. 



(3) The Tragulina or Chevrotains. These are diminutive 



deer-like animals, and they^were formerly thought to 

 be like the musk-deer. 



(4) The Pecora, or true ruminants, comprising the deer, 



giraff'es, antelopes, sheep, goats, and oxen. 



These Artiodactyle Ungulata, as their name implies, are pro- 

 vided with an even number of toes, while the other group of 

 Ungulates called the Perissoductyles, have either one toe only or 

 three. Now, we must here point out, however, that although 



