NERVOUS SYSTEM. VERTEBRATA. 319 



Family HIPPOPOTAMWJE. 



D. 417. The brain of a new born Hippopotamus (Hippopotamus 

 amphibius). 0. 0.1328 L. 



D. 418. The brain of a Hippopotamus (Hippopotamus amphibius) , 

 (<?), (figs. 185 & 186). 



In comparison with the dimensions of its body the 

 Hippopotamus has a remarkably small brain. Thus the 

 brain is smaller than that of the Horse, in spite of the fact 

 that the Horse is about one-fifth the weight of the Hippo- 

 potamus : an Elephant of approximately the same size as a 

 Hippopotamus has a brain more than five times as large. 



Fig. 185. (xf.) 



SULC.LAT. 



SULC.P. SYL 



OLF. BULB. 



This points to the conclusion, which is supported by the 

 general evidence of Comparative Anatomy, that the Hippo- 

 potamus is an instance of the persistence of a primitive 

 small- brained mammal in virtue of the faot that it has 

 maintained itself in the fierce struggle for existence simply 

 by pursuing an eminently safe and retired mode of life. 

 The cunning and alertness of the mammal living in the 

 open thus cease to have that vital importance which implies 

 one or other of the only alternatives a large brain or 

 extinction (Max Weber, Kon. Ak. v. Wetens. t. Amsterd. 

 1896). 



