IO26 



THE UNGULATES, OR HOOFED MAMMALS 



of the lower, or just the reverse of what occurs in the true pigs. This differ- 

 ence in the proportionate length of the upper and lower tusks in the two groups is 

 due to the circumstance that in the wart hogs the lower pair only bite against the 

 inferior surface of the upper ones, instead of abrading their whole summits. The 

 upper tusks are devoid of enamel except at their tips, and these small caps are worn 

 away at an early period. They curve in an upward and inward direction, and some- 

 times project as much as eight and three-fourths inches from the jaw, having a basal 

 girth of five inches. The shorter and more slender lower tusks have a nearly simi- 

 lar curvature, and are coated throughout with enamel. 



The tusks are not, however, the only peculiarity in the dentition of the wart 

 hogs. In young animals there are thirty-four teeth, namely, one pair of upper and 

 three pairs of lower incisors, a pair of tusks in each jaw, and six cheek-teeth on 

 each side of the upper, and five in the lower jaw. In the adult, the incisors and 

 anterior cheek-teeth tend, however, to disappear, till in some instances the tusks and 

 the last molars alone remain, thus leaving a total of eight teeth. This paucity in 

 the number of cheek-teeth is compensated, however, by the enormous size and com- 

 plex structure of the single molar remaining in each jaw. The tooth in question is 

 composed of a number of small, elongated, cylindrical denticles, closely packed to- 

 gether; its total length from back to front, being something over two inches, and its 

 height proportionately great, although its width is small. This is, however, only 

 an extreme development of the structure already referred to as occurring in certain 

 extinct species of the genus Sus; and in possessing such a single tooth on each side 

 of the jaws in the adult condition, the wart hogs may be compared to the elephants. 

 The body in these animals is massive and nearly cylindrical, the ears are small 

 and sharply pointed, the tail is long and tufted at the tip, and the neck and back are 

 furnished with a mane of long bristly hair, the rest of the body being nearly naked. 

 The young are uniformly colored. 



Of the two species, ./Elian's wart hog (Phacochcerus africanus) (figured on p. 

 1025) is distributed over a large part of the eastern side of Africa, ranging as far 



north as Abyssinia. On 

 the other hand, Pallas' s 

 wart hog (P. pallasi], of 

 which the head is here 

 figured, is confined to 

 Southeastern Africa. Both 

 species stand about 

 twenty-seven and one-half 

 inches at the shoulder. 

 The second is distin- 

 guished from the first 

 species by its shorter head, 

 which is more convex be- 

 tween the eyes; and it has 

 also the warts below the 

 latter very long and pendent, instead of projecting outward, while the tusks are 



HEAD OK PAU,AS'S WART HOG. 



(From Sclater, Proc. Zool, Soc., 1869.) 



