648 Doubts respecting 



landii, and has on the contrary something of the character 

 which we have just described in the Tupaia, 



I shall not dwell upon the manner in which the latter jaw 

 terminates anteriorly, because it is possible that there is here 

 also some mutilation. It roust indeed have been so consi- 

 dered by the late M. G. Cuvier, since he regards all the re- 

 maining teeth as grinders ; I shall therefore confine myself to 

 observing, that this mode of terminating in a point, is much 

 the same as obtains in fishes and reptiles, but this we have 

 already pointed out in the Tupaia. 



I shall however insist more largely upon the system of den- 

 tition. We have seen above that in the first half jaw from 

 Stonesfield the system consists of a regular and uninterrupt- 

 ed series of ten subequal teeth, subsimilar, with a crown very 

 much compressed, tricuspid, extremely small or low when 

 compared with their very long roots ; and these latter formed 

 of two radicles or branches, both very much pointed, entirely 

 buried in the jaw, and without any dental canal beneath 

 them. 



Now in considering all these teeth as molars, as M. Cuvier 

 has done, and it is difficult to do otherwise, it is evident that 

 there is no comparison to be established with what we have 

 just described in an insectivorous didelph or monodelph. 



None of these animals have more than seven molars. 



In none of them are they regularly separated by interspaces. 



In none of them are they so nearly similar, those in front 

 being scarcely smaller than the hinder ones. 



We may also add that none of them have these teeth so 

 disproportionate in their crowns and roots. 



Finally, if the first false molars of the opossums offer some 

 resemblance to the first molars of the Did. Prevostii in hav- 

 ing two roots, and the crown compressed, — yet here all re- 

 semblance ceases ; and to the other molars there is actually no 

 approach to be made in the way of comparison ; those of the 

 fossil being compressed and palmate, with three or four tu- 

 bercles, the largest occupying the middle of the tooth ; while 

 those of the insectivorous mammals are always thick, sub- 

 quadrate, with a dilated crown, raised, divided into two parts 

 by a deep median depression, and each part beset with points 

 without and within. 



Finally in the fossil, notwithstanding the destruction of the 

 external plate, and of a part of the horizontal ramus, an ac- 

 cident which lays open to view the situation of the seven first 

 teeth, we perceive no trace of the dental canal, which in all 

 the Mammalia runs through the whole extent of the jaw; 

 and furthermore it appears, to judge from the representation, 



