374 THE ANATOMY OF YEETEBEATED ANIMALS. 



cannon bone, and the fifth digit of the pes is represented 

 only by its metatarsal. 



In PliacocluBrus (the Wart-hog) the upper incisors are re- 

 duced to one pair, and the hiudermost molars, which are 

 the only ones which are not shed in the old animal, are of 

 great size, and possess a complicated, tuberculated, struc- 

 ture. 



The Suidce are represented by one genus or another in 

 all the gi'eat distributional provinces except the Australian* 

 and Novo-Zelanian. Porcus is peculiar to part of the 

 Malay Archipelago, Dicotyles to South America, and Pha- 

 cochcerus to South Africa. 



A gi-eat variety of Swine-like Ungulcda existed during the 

 deposition of the older tertiary strata, and are the earliest 

 known members of the group. 



b. The Hippopotmnidce are represented at present only 

 by the genera Hippopotamus and Chceropus. These animals 

 have a huge head, a heavy body, covered with a thick in- 

 tegument, provided with scanty hairs, and short, stout, 

 tetradactyle limbs, all the foiu- toes of which rest on the 

 ground. The female has inguinal teats, and the male is 

 devoid of a scrotum. 



2*2 



The dental formula of the adult Hippopotamus is i. — 

 c. ^- p.7)i. —^ m. -^, while Chceropus has only two incisors 



in the lower jaw. The tubercles of the molar teeth, when 

 ground down by mastication, present a double trefoil 

 pattern, and the hiudermost inferior molar is trilobed. 

 The incisors are straight and tusk-like. The very large 

 and curved canines are directed downwards in the upper 

 jaw, upwards in the lower. Their mutual attrition wears 

 the anterior face of the extremity of the upper, and the 

 posterior face of that of the lower, flat. 



The milk dentition consist of d.i. -~ d.c. — - d.m. 7—. The 



S'3 1 ■ I 4 4 



last lower deciduous molar is trilobed, and the first deciduous 

 molar persists a long time, and seems not to be replaced. 

 * The Papuan pig may have been introduced from the westward. 



