26 U. S. P. R. R. EXP. AND SURVEYS ZOOLOGY GENERAL REPORT. 



the former, however, occurring abundantly also as a fossil genus, in America as well as the Old 

 World. The teeth differ much from those of the other families, in the constant absence of canine?, 

 and of lower incisors in any but very young animals. 



2. Genuina. The members of this family are distinguished from the ProbosciJea by the absence of the elongated, prehensile 

 nose; and by the existence of small canines, instead of the enormous tusks, as well as of incisors in both jaws. The feet are 

 three or four toed, with hoofs of unequal size, the limbs are short, the body, neck, and head more elongated. The body in 

 usually full and rounded, the skin very thick and naked ; the nose and ear flap much developed. 



The living genera of this family are Tapirus, Rhinoceros, Hippopotamus, and, according to 

 Giebel, Hyrax. The most important of the fossil are Palaeotherium, Titanotherium, Anchi- 

 therium, Lophiodon, Anthracotherium, &c., many of these with North American representatives. 



3. Suina. Animals of comparatively small size. More compressed body, pointed head, large ears, blunt snout, slender, 

 thin legs ; hoofs arranged in pairs, and the skin covered with rather close bristly hairs. 



The living genera of this family consist of Sus, Dicotyles, Porcus and Phacochoerus, the fossil 

 chiefly of Entelodon, Ghoeropotamus, Hyopotamus, Hyotherium, Adapis, &c. } nearly all with 

 North American representatives in the bone beds of the Mauvaises Terres. 



The genus Sus embracing the common hog is characterized by having four-toed feet, and in 

 being without any gland on the back or fleshy lobes on the face. Dicotyles, with two species, 

 one of them the common Peccary of Texas, has differently constituted canines, but three toes on 

 the hind feet, a very rudimentary tail, and a peculiar gland on the back. 



The genus Porcus, with the well known Babyroussa as its type, is chiefly characterized by its 

 enormous canines, which curve upwards and outwards in a large semicircle. 



The remaining genus, Phacochoerus, or wart hog, has the minimum number of incisor and 

 molar teeth in the family, four-toed feet, four fleshy lobes on the face, large tusks, and a com 

 pressed and powerful body. 



4. Toxodontidae. This family and the next, 5. Anoplotheridae, are composed entirely of extinct genera and species, some of 

 which belong to our continent, the Toxodontidae, indeed, restricted to South America. It is in the Anoplotheridae that we find 

 the transition from the Pachydermata to the Ruminantia. 



It is much to be regretted that in his account of the fossil genera and species of the Pachyder 

 mata, Giebel should have entirely lost sight of the numerous species from North America, so 

 ably and satisfactorily defined by Dr. Leidy. 



