HIPPOPOTAMUS. 5G3 



tamus ; but exhibits as strong a tendency towards the Hippopotamoid 

 family as that does towards the plantigrade Carnivora. 



HIPPOPOTAMIDJE. 



204. Hippopotamus. — ^The tendency to excessive and, as it may be 

 termed, monstrous development, which characterises the canine teeth 

 in the typical Suidce affects both these and the incisors in the present 

 remarkable family, of which the Hippopotamus of the great rivers of 

 Africa is now the sole existing representative. Figure 4 in PI. 141 

 gives an oblique view of the formidable apparatus of variously 

 directed prominent incisive and canine tusks in this animal. The 

 upper incisors, two in each intermaxillary bone, curve downwards 

 and oppose their extremities to the sides or upper surface of 

 the straight and porrect incisors, also four in number, in the lower 

 jaw ; and they thus repeat in their relative position the characters 

 of the upper and lower incisors of the Suidfs. The mid-incisor above 

 (i l)is subcylindrical, slightly curved, with the apex obliquely abraded 

 along the inner side : the outer incisors {i 2) are placed behind and 

 to the outer side of the median pair, are more curved, and oppose 

 themselves more directly to the outer pair below. 



The two median inferior incisive tusks are cyhndrical, of great 

 size and length, obUquely abraded at the upper and outer part of their 

 extremity : the basal portion which is lodged in the deep alveolus is 

 longitudinally grooved : the two outer incisors are likewise cylindrical 

 and straight, are much smaller and are worn towards the inner side of 

 their point. The upper canines (c) curve downwards and outwards, 

 their exposed part is very short and is worn obliquely at the fore 

 part, from above downwards and backwards ; they are three-sided, 

 with a wide and deep longitudinal groove behind. The lower 

 canines (c) are extremely massive and large, curved in the arc of a 

 circle, subtrihedral, the angle rounded off between the two anterior 

 sides, which are convex and thickly enamelled, the posterior side 

 of the crown being almost wholly occupied by the oblique abraded 

 surface opposed to that on the upper canine. 



The implanted base of each of these incisive and canine teeth 

 is simple and excavated for a large persistent matrix contributing to 



o o 2 



