THE HOOFED MAMMALS. 



131 



FUj. 71.— Common Hippopotamus 

 (^Hippoziotamus amphibius). 



members of the Artiodactyla, and are characterised as a family by the follow- 

 ing features. Having a very bulky, clumsily-built body, and short limbs, 

 these animals possess a very broad and obtuse muzzle ; the feet are short 

 and broad, each having four toes of nearly equal size, invested in rounded 

 hoofs, and all applied to the 

 ground in walking ; the incisor 

 teeth, -which grow throughout 

 life, are curved downwards in the 

 upper jaw, and project straight 

 forwards in the lower ; and the 

 canines, which also grow con- 

 tinuously, are very large and 

 curved, those of the upper jaw 

 being directed downwards. The 

 molar teeth are tuberculated, and 

 have four columns, the summits 

 of which show trefoil - shaped 

 surfaces of ivory, bordered by a 

 broad rim of enamel, when worn 

 by use. In the head, the great 

 elongation of the face causes tlie 

 small eyes and still more minute 

 ears to be situated very far back- 

 wards ; the legs are so short that the lower surface of the body is scarcely 

 raised above the ground in the standing posture ; and the round tail is likewise 

 extremely short. The tliick skin is almost entirely naked. The common 

 hippopotamus (H. ampliibius) is an animal too well-known, both as regards 

 form and habits, to require any detailed description ; its most distinctive 

 feature being the possession of two pairs of incisor teeth in each jaw. On 

 the West Coast of Africa there exists, however, in Liberia, «, second species of 

 the genus, known as the pigmy hippopotamus (H. liberieiisis), differing not 

 only in size, but likewise in habits, from the one with which all are 

 familiar. In place of attaining a total length of about 11 feet, mea- 

 sured in a straight line, and weighing probably some three or four 

 tons, the pigmy hippopotamus is not larger than a good-sized wild 

 boar, although it has the short and stout limbs of its gigantic cousin, 

 with which it also agrees to a certain extent in tlie relatively large 

 size of its head. As regards its mode of life, this species differs, how- 

 ever, in toto from the common one. Instead of passing at least as much of its 

 time in the water as on the land, and never living away from rivers or lakes, 

 the pigmy hippopotamus is an inhabitant of the dense tropical forests of that 

 part of \Vestern Africa which is its home, where it apparently leads a life very 

 similar to that of wild pigs, wallowing in swamps after the manner of tliose 

 animals, but apparently not habitually frequenting rivers, though it is doubt- 

 less, like almost all Mammals, able to swim well when the necessity arises. 

 Moreover, in place of associating in large herds after the manner of tlie 

 common species, and never moving far from one particular locality, the 

 Liberian hippopotamus is a comparatively solitaiy creature, going about at 

 most only in pairs, and wandering long distances through the woods. It 

 differs essentially from the common species in usually having only a single 

 pair of lower incisors, on which account it has been generically separated by 

 Bome under the name of Cliixrojmis. Specimens are, however, occasionally 



