ELEPHAS PRIMIGENIUS. 227 



those teeth, in the important question of the species or 

 varieties of Mammoth that formerly inhabited England. 



The crown of the molar of the Mammoth, like that of the 

 existing species of Elephant, consists of, or is divided into, 

 a number of transverse perpendicular plates, composed of 

 two distinct substances, and cemented together by a third 

 substance. The body of each plate consists of the basal 

 constituent of a tooth called " dentine," of which ivory 

 is a modification ; it is marked e?, in the figures of the 

 teeth in this section. The dentine is coated by a layer 

 of harder substance called "enamel" (0), and the inter- 

 spaces of the plates so formed are filled by a less dense 

 substance called "cement" (c), because it fastens together 

 the several divisions of the crown, and more strikingly 

 fulfils the office of cement when those divisions are incom- 

 pletely formed and not united by mutual confluence. 

 As the growth of each plate begins at the summit, they 

 remain detached and like so many separate teeth or denti- 

 cules, until their base is completed, when it becomes ex- 

 panded and blended with the bases of contiguous plates to 

 form the common dentinal body of the crown of the com- 

 plex tooth, from which the roots are next developed. 



But the composition and growth of the plates are analogous 

 to, and almost as complex as, that of the entire tooth ; each 

 plate consists at first of a series of separate slender 

 conical columns or digital processes, arranged transversely 

 across the tooth. The formation of these columns begins 

 at their summit, and descends, their bases gradually ex- 

 panding until they are blended together to form a continu- 

 ous transverse plate ; just as the plates are subsequently 

 blended together to form the continuous longitudinal crown 

 of the whole grinder. The digital processes and the 

 digitated plates of an incompletely developed tooth are held 



