TEETH OF THE ELEPHANT. 279 



The plates of the mohir teeth of the Siberian mammoth 

 (Flejjhas pnmigemus\ (Fig. 74), are thinner in proportion 

 to their breadth, and are generally a little expanded at 

 the middle ; and they are more numerous in proportion 

 to the size of the crown than in the existing species of 

 Asiatic elephant {ih). In the African elephant {ih)^ on 

 the other hand, the lamellar divisions of the crown are 

 fewer and thicker, and they expand more uniformly from 

 the margins to the centre, yielding a lozenge-form when 

 cut or worn transversely, as in mastication. 



The formation of each grinder begins with the summits 

 of the anterior plate, and the rest are completed in suc- 

 cession; the tooth is gradually advanced in position as its 

 growth proceeds ; and in the existing Indian elephant the 

 anterior plates are brought into use before the posterior 

 ones are formed. "When the complex molar cuts the gum, 

 the cement is first rubbed off the digital summits; then 

 their enamel cap is worn awaj^, and the central dentine 

 comes into play with a prominent enamel ring ; the digi- 

 tal processes are next ground down to their common 

 uniting base, and a transverse tract of dentine, with its 

 w^avy border of enamel, is exposed; finally, the trans- 

 verse plates themselves are abraded to their common 

 base of dentine, and a smooth and polished tract of that 

 substance is produced. From this basis the roots of the 

 molar are developed, and increase in length to keep the 

 worn crown on the grinding level, until the reproductive 

 force is exhausted. When the whole extent of a grinder 

 has successively come into play, its last part is reduced to 

 a long fang, supporting a smooth and polished field of 

 dentine, with, perhaps, a few remnants of the bottom of 

 the enamel folds at its hinder part. W^hen the complex 



