THE MASTODON 201 



the object of this being the same in both tooth 

 and chisel, to keep the edge sharp by wearing 

 away the softer material. In the case of the 

 chisel this is done by a man with a grindstone, 

 but with the tooth it is performed automat- 

 ically and more pleasantly by the gnawing of 

 food. In the mastodon and elephant the tusks, 

 which are the representatives of the cutting 

 teeth of rodents, are wide apart, and of course 

 do not gnaw anything, but the presence of 

 these enamel bands hints at a time when they 

 and their owner were smaller and differently 

 sliaped, and the teeth were used for cutting. 

 Thus, great though the disparity of size may 

 be, there is a suggestion that through the mas- 

 todon the elephant is distantly related to the 

 mouse, and that, could we trace their respec- 

 tive pedigrees far enough, we might find a com- 

 mon ancestor. 



This presence of structures that are appar- 

 ently of no use, often worse than useless, is 

 regarded as the survival of characters that once 

 served some good purpose, like the familiar 

 buttons on the sleeve or at the back of a man's 

 coat, or the bows and ruffles on a woman's 



