264 ECONOMIC ZOOLOGY 



even- toed forms; the Peris sodactyla or odd- toed forms; and the Pro- 

 boscidea, the elephants. Besides these another related group, the 

 Hyracoidea, not true ungulates, includes the small oriental animal, 

 the "coney," mentioned in the Bible. 



The ungulates are usually large animals whose digits end in horny 

 hoofs. They are herbivorous and are generally covered with hair or 

 bristles, rather than with fur. The canine teeth are usually absent 

 or rudimentary and the back teeth are adapted for grinding. 



The artiodactyla include most of the game animals and the domestic 

 forms that are used for food, such as the deer, sheep, cattle, goats, 

 pigs, camels, giraffes, hippopotami, etc. Most of these even-toed 



FIG. 172. Stomach of ruminant opened to show internal structures, a, 

 oesophagus; b, rumen; c, reticulum; d, psalterium; e, abomasum; /, duodenum. 

 (From Hegner, College Zoology, after Flower and Lydekker.) 



forms are known as ruminants from their habit of eating vegetation 

 rapidly and later regurgitating it from a storage pouch or rumen and 

 then chewing it thoroughly for digestion in the other parts of the 

 stomach, Fig. 172. The hog is the most familiar of the non-ruminating 

 artiodactyla. The perissodactyla include the horse, ass, zebra, 

 tapir, rhinoceros, etc., none of whom are ruminants. 



Most of the ungulate animals are so familiar that no further de- 

 scription will be necessary. 



The most important of the ungulats are, of course, the ordinary 

 domestic animals, but of these but little need be said here, since libraries 

 have been written upon the different aspects of this important subject. 



The United States is the greatest meat-producing and meat- 

 consuming country in the world. In the huge packing houses of 



