222 JEL JANS' WART-HOG. 



alveolae. The third, (in the upper jaw, and the 

 second in the lower,) is strong, and as broad as 

 the fourth ; its enamel surface contains five crown- 

 globules, four of which occupy the corner, and 

 one the middle. It is wedged into four separate 

 alveolae, by means of four roots. 



With regard to these three first back teeth 

 we would remark, that as age advances they 

 gradually disappear, and none remain except the 

 anterior ones. In one animal, greatly advanced 

 in age, we find all three of them almost entirely 

 destroyed. The third is diminished by two-thirds, 

 and nothing remains of it but the crown surface, 

 which keeps its position only by being wedged 

 in between the fourth large one, and the second 

 back tooth ; whilst the alveolae, which held it* 

 roots, have entirely vanished. But even this 

 animal had all its upper and lower incisors 

 still, although in a somewhat worn-out state. 

 Fred. Cuvier, in explaining this circumstance, 

 shews, that the fourth or posterior back tooth, 

 which, in growing, is pushed forward towards the 

 front, in the same manner as we find this in the 

 Elephant, causes thereby the falling out of the ante- ' 

 rior teeth. We admit the soundness of this view, 

 and readily believe that the continual growing of 

 the posterior back tooth should injure and remove 

 the anterior ones, or even cause them to fall out. 

 But besides, our attention has been directed by 



