440 



UNGULATES. 



and these small caps are worn away at an early period. They curve in an upward 

 and inward direction, and sometimes project as much as 8f inches from the jaw, 

 having a basal girth of 5 inches. The shorter and more slender lower tusks have a 

 nearly similar 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 complex 

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

 composed of a number of small elongated cylindrical denticules, closely packed 

 together ; its total length from back to front, being something over 2 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 coloured. 



Of the two species, ^Elian's wart-hog (Phacochoerus africanus) (figured on 

 p. 439) 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 South-Eastern 

 Africa. Both species stand 

 about 27 J inches at the 

 shoulder. The second is 

 distinguished 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 pen- 

 dent, instead of projecting 

 outwards, while the tusks are more inclined outwards. The mane is also wider 

 and shorter, and there is a greater development of hair on the top of the 

 head and the ears. It has also been considered that it is only this species in 

 which all the teeth, except the tusks and last molars are habitually shed, but 

 this is doubtful. The colour of Pallas's wart-hog is redder than that of its 

 northern relative. 



HEAD OF PALLAS'S WART-HOG. 

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



