ELEPHANTS. 253 



African elephant has a convex forehead ; it is not now 

 FIG. 194. 



Heads of (A) African and (B) Indian Elephants. 



FIG 195. 



domesticated, and has not been for many centuries. 

 This animal is destructively 

 hunted for its tusks, which 

 furnish the valuable ivory 

 of commerce. 



The two enormous spe- 

 cies of fossil mammals 

 known as mammoth and ^""^ZT "' 

 mastodon belonged to the 



class proboscidia, and differed but little from the ele- 

 phants in organization and in habit. 



PERISSODACTYLA. 



The perissodactyla are classified in three families, 

 represented by the horse, the tapir, and the rhinoceros. 



22 



