TEETH OF ANIMALS. 263 



the rodeiitia, on the other hand, the line of the 

 enamel of the grindmg teeth runs transversely to 



The li;iuie represents the molar tooth of the horse, and exhibits 

 the roughness of its upper suiface, and the depth of the body of 

 the tooth in the jaw commensurate to the pressure if bears. 



the jaw ; and in mastication, the jaw is draw 

 backwards and forwards, not laterally. This 

 original composition of a grinding tooth is, there- 

 fore, superior to the best mill-stone. The rough- 

 ness, which is so like a thing accidental, is found 

 to proceed from an arrangement in accordance 

 with the motion of mastication. It might, in like 

 manner, be easily demonstrated, that there exists 

 a similar accordance with the form of the jaw and 



