170 



DIFFERENT KINDS OF TEETH. 



and in many animals (especially those of carnivorous habits) 

 project far beyond the former ; they are adapted not to cut 

 the food, but, by being deeply fixed in it, to enable the 

 animal to tear it asunder : these are termed canine teeth. 

 The teeth of the third kind have large irregular flattened 

 surfaces, and are adapted to bruise and grind the food ; these 

 are called molar (or mill-like) teeth. The manner in which 

 these different teeth are implanted in the jaw, varies with the 

 form of their crowns, and is in accordance with their several 

 uses. The incisors, whose action tends as much to bury 

 them in their sockets as to draw them forth, have but a single 

 root or fang of no great length. The canine teeth, on which 

 there is often considerable strain, penetrate the jaw more 

 deeply than the incisors ; especially when they are large and 



Molars. Bicuspid. Canine. 



Fig. 93. HUMAN TEETH. 



long, as in the Cat tribe (fig. 94). And the molars, whose 

 action requires great firmness, have two, three, or even four 

 roots or fangs, which spread out from each other ; and these 

 at the same time increase the solidity of their attachment to 

 the jaw, and prevent the teeth from being forced into their 

 sockets by any amount of pressure. 



182. The arrangement of the dental apparatus varies, in 

 different Mammalia, according to the nature of the aliment 

 on which they are destined to feed ; and this correspondence 

 is so exact, that the anatomist can generally determine by the 

 simple inspection of the teeth of an animal, not only the 

 nature of its food, but the general structure of the body, and 

 even its ordinary habits. Thus, in those that feed exclusively 

 on animal flesh, the molar teeth are so compressed as to form 



