44 THI-: MAMMALIA. 



11 though, in most cases, this takes place 

 \\iili the utmost slowness. Instances of the loss of 

 milk trrth arc met with among the Marsupials and 

 seals. Tin- whole phenomenon belongs to the 

 chapter of 'abbreviated development.' It was our 

 intention here merely to point out this view of the 

 suhject, in order to make use, in what follows, 

 of the designations given to different parts of the 

 jaw, according to position and time, since Cuvier's 

 and Owen's classical investigations. 1 



Let me here repeat that the specialisation of 

 I'-ntition frequently runs parallel with a speciali- 

 sation of the limbs. Thus, in comparison with its 

 geological ancestors, the dentition of the horse is 

 specialised, and this is equally evident as 

 <ls its foot, the transformation of which, from 

 a live-toed member not specially suited either for 

 running, grasping, or climbing into a one-hoofed 

 member, so admirably adapted for running, has 



/<?. In man the milk teeth, the denies dccidui, con- 

 sist of the cutting teeth (incisors), the canine or eye teeth, and 

 o front cheek-teeth. In addition to these there are the 

 back cheek-teeth that have no predecessors. The teeth of the 

 full-grown man are indicated thus : i \ c } p m i], i.e. on either 

 below two incisors, one canine, two premolars 

 and t m. Although Cuvior of course knew th> 



ds lait and de rcntpluccmcnt, still Owen was the lirst 



rigorously to carry out the designation. 



