284 DEVELOPMENT OF ELEPHAXT's GRINDERS. 



ceecls three inches and a half. One may reasonably con- 

 jecture that the sixth molar of the Indian elephant, if it 

 make its appearance about the fiftieth year, would, from 

 its superior depth and length, continue to do the work of 

 mastication until the pondrous pachyderm had passed 

 the century of its existence. 



Development. — The long-mistaken phenomena of the 

 formation of the dental substances will be here described 

 as ishey have been observed in the large teeth of the ele- 

 phant; if the description be comprehended in regard to 

 these, the most complex members of the dental system, 

 the true theory of dental development will be readily 

 understood in regard to all the various forms and grada- 

 tions of teeth. The matrix, or formative organ of the 

 tusk, consists of a large conical pulp, which is renewed 

 quicker than it is converted, and thus is not only pre- 

 served, but grows, up to a certain period of the animal's 

 life; it is lodged in the cavity at the base of the tusk; 

 this base is surrounded by the remains of the capsule, a 

 soft, vascular membrane of moderate thickness, which is 

 confluent with the border of the base of the pulp, where 

 it receives its principal vessels. 



Each molar of the elephant is formed in the interior 

 of a membranous sac — the capsule, the form of which 

 partakes of that of the future tooth, being cubical in the 

 first molar, oblong in the last, and rhomboidal in most of 

 the intermediate teeth; but alwaj^s decreasing in vertical 

 extent towards its posterior end, and closed at all points, 

 save where it is penetrated by vessels and nerves. It is 

 lodged in an osseous cavity of the same form as itself, 

 and usually in part suspended freely in the maxillary 

 bone, the bony case being destined to form part of the 



