MAMMALS. 



397 



The ANTHRACOTHERIID^, best developed in the European upper eocenev 

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

 each foot, the outer ones in process of reduction. Anthracotheriutn, eocene. 

 Hyopotamus, miocene of the U. S. and Europe. The SUID^E, 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 \ or |, c \, 

 p to f , m , 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/E) occurring 

 in the western hemisphere. In 

 Achcenodon, from the eocene, there 

 are already developed the tusk-like 

 canines so characteristic of mod- 

 ern swine ; in Elotheriiim they are 

 less conspicuous, while in Chcero- 

 potamus (eocene, Europe) and 

 Leptockarits (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 / , c \, p f , m f ; the fifth 

 toe of the hind feet lacking, and 

 the stomach more complex than 

 in the typical s wines. The spe- 

 cies are gregarious and omnivor- 

 ous. The allied Platygomis is 

 pliocene. In the pigs proper 

 Sits, Babirusa. Phacochcents 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- 

 tinguished by the dentition : Sns, i f , c \, p |, ;// \ ; Babirnsa, i\,c\,p\< m \'i 

 Phacochcerns, i\, c\,p\, m \. 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 Babinisa (Porcns~) 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 {Phacocheerus} 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. 

 i to \ , c \, p |, in |, the lower incisors very long and rootless. The metapo- 

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



FIG. 367. Stomach of sheep, after Cams' 

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

 sum; re, reticulum; ru, rumen. 



