IN THE LOWER ANIMALS, ETC. 



331 



teeth, owing to the great admixture of animal 

 food, suffer but a moderate amount of abrasion, 

 and they are supplied with roots, as in the 

 human subject. 



In those rodents which employ their teeth ex- 

 clusively for the comminution of woody fibre and 

 other coarse vegetable matters, as the beaver, 

 the reproductive power of the formative organs 

 is exerted through the greater part of the animal's 

 life, but at length the enamel organ becomes 

 obhterated; and as age advances, roots are 

 developed, supplying an imperfect substitute for 

 the crown, as we observed in the grinders of the 

 horse. 



But the capybara (Figs. 53 and 54) supplies an 



Fig. ^'i.— Skull of Capybara, showing the great solidity of the sockets of 



Teeth. 



EiG. 54. — Skull of Capybara, showing ante-orbital fossa. 



example of molar teeth which, like the incisors, 

 have a hollow base and a uniform shape from the 



