THE MASTODOii, 91 



by a small ridge, the last four flat-crowned. In the 

 lower jaw the first three molars were pointed and 

 trenchant, the remainder flat-crowned and tuberculous, 

 like those above opposed to them. (Fig, 46.) Of the 

 genus, Didiobunes contains three species, D. leporiJium, 

 murinum, and obliquum: the first about the size of a 

 hare ; the other two, of a guinea-pig. They appear to 

 have had much of the form, and probably of the habits, 

 of the little musk-deer, or chevrotains. 



The Mastodon. 



Coexistent perhaps with the mammoth, a race of huge 

 animals, now. utterly extinct, once tenanted our globe : 

 their remains, which are met with in the superficial strata, 

 occur in some localities in great abundance ; and, from 

 the differences presented by the teeth and other parts, 

 several species have been identified. To these animals 

 Cuvier gave the title of Mastodon, in allusion to the 

 principal character of the molars, which, instead of being 

 formed, as in the elephant, of transverse laminae, have 

 the crown of simple structure, but exhibiting ranges of 

 bold conical elevations, divided from each other by deep 

 fuiTOws. (Fig. 47.) As the points of these elevations 

 become worn down by use, the crown presents a series 

 of lozenge-sliaped lines of thick enamel (Fig. 48), but 

 when these are quite obliterated the surface becomes 

 uniform and concave. 



Of the molars thus characterised there were two above 

 and below on each side ; but before these molars it 

 would appear that in young individuals others had been 

 situated, and had fallen in succession, as Cuvier satis- 

 factorily ascertained from the examination of various 

 specimens. With regard to the mode of succession in 

 the grinders of the mastodon, it takes place, says Cuvier, 

 by a movement from behind forwards. When the back 

 tooth is in the act of piercing the gum, that anterior to 

 It is worn and ready to fall, and they thus replace them- 

 selves one after the other. It does not appear that it is 

 possible for more than two at a time on each side to be 



