MASTODON ANGUSTIDENS. 285 



in fact, which strictly correspond with the deciduous teeth 

 of ordinary Pachyderms. Cuvier's specimen shows the 

 first of the series of permanent teeth just coming into 

 place, with its mastoid eminences fresh and unworn ; 

 this permanent tooth, the only one corresponding to the 

 teeth called premolars, false molars, and bicuspides in 

 other Mammalia, is developed above the deciduous molars 

 in the upper jaw, beneath them in the lower jaw, and 

 it succeeds and displaces them vertically in both jaws. Its 

 crown is divided into four tubercles, and it is consequently 

 more simple than the second deciduous tooth which it 

 displaces, agreeing in this respect with the premolar teeth, 

 or dents de r "emplacement, in other Mammalia. 



When the milk-teeth are shed, and their quadri-tuber- 

 culate successor is in place, the molar tooth (fig. 100) is 

 the second of the molar series, but presents a character 

 which must seem strange to one unacquainted with the law 

 of the succession of teeth in the Mastodons, viz., a much 

 more abraded crown than the smaller tooth which pre- 

 cedes it. The smaller tooth is therefore the first of the 

 permanent series of molars, and the one figured in cut 100 

 is the second of that series ; but, although they are termed 

 permanent molars, agreeably with the general analogies 

 of the Mammalian dentition, their duration is brief in 

 comparison with the life-time of the animal ; and they 

 are successively shed, as in the Elephant, the Hog, and 

 the Kangaroo, from before backwards ; the dentition in the 

 Mastodon being ultimately reduced to the last great molar 

 tooth, which is the seventh in the order of development. 



To facilitate the determination of the teeth of the 

 Mastodon angustidens, I shall briefly denote their general 

 characters, as they succeed each other in the order of their 

 development. 



