MAMMALIA 109 



while the other [Ph. Africanus) is much more widely distributed. 



In Celebes and the adjacent islands a remarkable pig is found 

 known as the Babirussa {Porcus babirussa), in which the lower 

 tusks are like curved daggers in shape, while the upper tusks 

 curve back over the face almost like horns. The natives say 

 that the animal hangs itself up by these when it wishes to sleep 

 peacefully. 



In America, from Mexico southwards, the pigs are represented 

 by small forms called Peccaries, one species being the Collared 

 Peccary {Dicotyles torquatus). 



B. Ruminants 



The members of this section agree with the pigs in possessing 

 on each foot only two toes which reach the ground, in addition 

 to which there may or may not be two smaller digits, but they 

 differ markedly from pigs in the greater length of their limbs, 

 which are eminently adapted for rapid progression. The most 

 characteristic feature, however, is to be found in the possession of 

 a very complex stomach, adapted for ruminating; i.e. the food is 

 first swallowed without chewing, and then returned to the mouth 

 in successive portions for leisurely mastication in a safe place. 

 The cheek teeth have grinding crowns, provided with crescentic 

 ridges, and (except in camels) the upper incisors are replaced 

 by a hard pad. The following families together constitute the 

 section: — i. Chevrotains; 2. Deer; 3. Prongbucks; 4. Oxen and 

 their allies; 5. Giraffes; and 6. Camels. 



I. The Chevrotains are a restricted group, including the 

 smallest and least specialized ruminants, approaching the peccaries 

 in some structural features. In appearance they suggest diminu- 

 tive hornless deer, and on this account are sometimes called 

 Mouse-Deer. There are no upper incisors, and the upper canines 

 of the male are slender, downwardly-directed tusks. Of the six 

 existing species five belong to the genus Tragulus, and are 

 distributed through South Asia from India eastwards. The 

 smallest species is the Malay Kanchil {Tragulus Javanicus) (fig. 

 75), than which only one other Ungulate, i.e. the Royal Antelope, 

 is of less size. The sixth species of this family is the Water 

 Chevrotain [Dorcatkerium aquaticum), which is only found on the 

 west coast of Africa. 



