280 



ZOOLOGY. 



(11-12 feet) in length, the circumference o± the body being 

 nearly the same. It is seldom over four and a half feet in 

 height. The hippotamus has been likened to a " form 

 intermediate between an overgrown hog and a high-fed 

 bull without horns and with cropped ears." Its incisor- 

 teeth attain at times two feet in length. The eyes, nos- 

 trils, and ears are all placed nearly on the same plane, 

 which allows the use of three senses and of respiration, a 

 very small portion of the animal being exposed when it 

 rises to the surface of the water. The legs are very short, 

 so that in some cases the belly almost touches the ground. 



Fig. 312.— Stomach of a ruminant, showing the four compartments: a, oesopha- 

 gus; b, paunch; c, honeycomb or reticulum; d. liber psalterium or many- 

 plies; e, true digestive stomach; /, beginning of the intestine. 



The hoofs are divided into four toes, not connected by 

 membranes. The skin is nearly an inch thick, and is naked. 

 The color of the animal when on land is of a purple brown, 

 but when seen at the bottom of a pool it appears to be dark 

 blue. It is thoroughly amphibious, swimming and diving 

 like a duck, but is slow and unwieldy on land. The hip- 

 popotamus feeds on grass, young reeds, and bulbous succu- 

 lent roots. It is gregarious, usually seen in troops of from 

 five to six to as many as twenty or thirty. It is nocturnal 

 in its habits, feeds by night, usually passing most of the 



