OF THE CLASS MAMMALIA. 285 



They live on vegetables, and their habitat is the rivers of 

 Central Africa.* Their colour is a brownish black, and they 

 attain an enormous weight. Three or four may be seen in a 

 line in the river, near some cataract or stream, darting at the 

 fishes which the rapidity of the current brings near them. 



Fig. 251. The Hippopotamus; the River Horse ; Sea Cow of the Dutch. 



They swim well and rapidly, and can remain a long time 

 under water. During the night they quit the rivers, and 

 feed on the herbage of the banks, or make their way to the 

 fields of rice or millet, which they rapidly consume. Their 

 march is so impetuous that they overthrow every obstacle, 

 especially when alarmed. Their character is ferocious. 



Fig. 252. Hippopotamus. 



The pig has also four toes on all the feet, but two are large 

 and two shorter.' The incisive teeth vary in number, and 

 the tusks protrude from the mouth, curling upwards. The 



* Southern and Northern as well. E. K. 



