114 CLASS MAMMALIA. 



led to suppose so, from a certain tendency to systematic 

 prejudices that exists in the minds of the greatest philoso- 

 phers. It is by no means uncommon for the corporeal eye 

 to see nothing but what has been perceived in anticipation 

 by the intellectual organ. 



Such are the differences upon which the distinction be- 

 tween the cephalotes and the roussettes has been founded. 

 Had it not been for the mantled roussette, the limits of the 

 two genera would have been still more strongly marked, 

 and the interval between them still wider. The mantled 

 roussette may be considered as a link uniting and attaching 

 together these two little tribes. 



We have remarked that these animals have four incisive 

 teeth in each jaw. M. Geoffroy asks, whether it be pos- 

 sible that the renewal or growth of certain teeth might oc- 

 casion the disappearance of others ? The falling out of the 

 incisive teeth, in the bats in general, is a case of common 

 occurrence. But this is a matter easy of observation, and 

 the progressive steps of which are obvious. These teeth, 

 fixed in a bed of no great depth, are but feebly retained by 

 the gums. As ossification advances, the alveolar cavity is 

 filled with more promptitude than in other animals, and it 

 is not astonishing that the incisives, under such circum- 

 stances, should be shaken and speedily disappear. But 

 this produces no influence or re-action on the canine teeth. 

 These being more deeply lodged in the maxillary bone, 

 preserve their position, and experience no other variation 

 than a slight degree of wear, in consequence of their mu- 

 tual friction. 



This being understood, it is easy to decide the question 

 as it regards the cephalotes. If the incisives fell from age 

 or accident, their places would be easily found. But in the 

 cephalotes there is no place which the incisors could pos- 

 sibly have occupied beyond the two which we have men- 

 tioned, The canine teeth, and the lower ones still more than 



