INSECTIVORES. 415 



incisors, as the true inferior canine : the fifth tooth is then the first 

 and largest of the series of four premolars, each of which has a small 

 posterior talon at the base of the compressed conical crown. The 

 three true molars are each implanted by two fangs and have quinque- 

 cuspid crowns, the middle molar being the largest. 



The teeth of the Mole have been differently classified by different 

 authors : the dental formula according to M. F. Cuvier(l) is : 



3-3 I-l 4-4 3-3 . 



m. — ; c. — : pm. — ; m. -— : = 44. 



4—4 ' 0-0 ' ^ 4—4 * 3—3 



Prof. Bell, in his " History of British Quadrupeds," (2) adopts the 

 following : 



3—3 1—1 7-7 . . 



m. — ; c. — ; m. — : = 44. 



4-4 ' 1— I ' 6-6 



Prof, de Blainville(3) prefers the formula : 



4-4 I— 1 3—3 3—3 



m. — : c. — : pm. — : m. — : = 44. 



4—4 * I— 1 * -'^ 3—3 ' 3-3 



From which it will be seen that the difference turns mainly 

 upon the determination of the canine teeth. M. F. Cuvier and Prof. 

 Bell both regard the fourth large tooth of the upper jaw as a 

 canine, notwithstanding it has two fangs. M. de Blainville(4) 

 has assured himself that it is an incisor, in which case the double 

 implantation would be still more anomalous. The position of the 

 incisive foramen (PI. 110, 3 a), however, indicates that the double 

 socket of this tooth is posterior to the intermaxillary suture, and 

 that the number of incisors has been rightly determined by F. 

 Cuvier. By this justly esteemed authority the canines are held 

 to be wanting in the lower jaw of the Mole. Prof. Bell regards as 

 lower canines the large fifth tooth on each side, although posterior 

 to the canine above ; and M. de Blainville, having assigned eight 

 incisors to the upper jaw, gives the same number to the lower 

 jaw, and calls the first premolar a canine. With regard to the 

 fourth tooth above, if it be not developed in the intermaxillary bone, 

 it claims to be regarded as a canine by the size and shape of the 

 crown, and to be a premolar by virtue of its two fangs ; but, since 

 the fang of a tooth is subject to more variety than the crown, we 



(I) Dents de Mammiferes, p. 61. (2) 8vo. 1837, p. 85. 



(3) Osteographie. (4) Loc. cit. 



