MAMMALS. 



39J 



The Anthracotheriid^, best developed in the European upper eocerrev 

 have the teeth / ^, c \, p \, in |, the metapodials distinct, and four toes on 

 eacli foot, the outer ones in process of reduction. Anthracotheriicm, eocene. 

 Hyopotamiis, miocene of the U. S. and Europe. The SuiD«, or swine, 

 apparently derivatives of the last family, appear in the eocene of both conti- 

 nents, and continue to the present time. They have the teeth i f or |, c \, 

 p \ \.Q> \, in \, the molars bunodont. The feet are four-toed, rarely three- 

 toed, toes 2 and 5 smaller than the others, and the metapodials distinct. 

 The stomach has a pouch developed near the cardiac opening ; the colon is 

 spirally coiled, and a caecum is present. The earlier history of the family is 

 less certain than that of some others, and some of the earlier genera seem to 

 have a carnivorous facies. The family to-day belongs to the old world, only 

 the peccaries (frequently set aside as a distinct family, Dicotylid«) occurring 

 in the western hemisphere. In 

 Achmnodon, from the eocene, there 

 are already developed the tusk-like 

 canines so characteristic of mod- 

 ern swine ; in Elolheriiun they are 

 less conspicuous, while in Chccro- 

 potamus (eocene, Europe) and 

 Leptochcsi-iis (miocene, U. S.) 

 these teeth are smaller. The pec- 

 caries {Dicotyles) appear in the 

 American pleistocene, and two or 

 three species persist in warmer 

 America to-day. They have the 

 teeth i I, c \, p f , m | ; the fifth 

 toe of the hind feet lacking, and 

 the stomach more complex than 

 in the typical swines. The spe- 

 cies are gregarious and omnivor- 

 ous. The allied Platygonus is 

 pliocene. In the pigs proper. — 

 Sns^ Bahh-usa. Phacochariis — the 

 canines are greatly developed and triangular in section, and a large diastema, 

 exists between these and the premolars. All are old-world forms, and are dis- 



FiG. 367. Stomach of sheep, after Carus- 

 and Otto (Oppel). a, abomasum ; w, oma- 

 sum; re, reticulum; ru. rumen. 



tinguished by the dentition : Sits, i\, c\,p^. 



; Babintsa, 



^P\ 



Phacochcertis, i\, c\,p\, in \. The true swine, Sus, appear in the pliocene 

 and continue as our domestic hogs, descended from the wild boar and other- 

 Asiatic species. The single species of .5rt^/r«ja {Parens') of the Malay Islands. 

 is remarkable in that the upper canines of the male grow upward through the- 

 skin of the snout. The wart-hogs of Africa {PJiacochcei-us) receive their' 

 common name from the projections on the face. In the adults many of the: 

 teeth are lost, but the canines form enormous tusks, both pairs curving 

 upwards and outwards. 



The HIPPOPOTAMID.E are large, amphibious, bunodont forms, with teeth, 

 the lower incisors very long and rootless. The metapo- 



to 



dials are distinct, the feet four-toed, the lateral toes being nearly equal to the- 



