ANATOMICAL PECULIARITIES OF TEETH. 211 



the conclusion that its peculiar form was due to changes 

 in the fang. 



From mammals we may turn our attention to snakes. 

 In toothed reptiles the teeth are attached to the jaw- 

 bone in a manner differing from that which pertains to 

 mammals. In the latter the teeth, as they develop, 

 become surrounded by walls of loose porous bone, forming 



FIG. 113. Section through the jaw and tooth of a Python, 

 showing bone of attachment. 



an alveolus ; when the teeth are erupted the roots or 

 fangs remain embedded in this imperfect kind of bone ; 

 hence, when a tooth is extracted, a socket, or empty 

 space remains, resembling that left by withdrawing a 

 nail from a piece of wood into which it has been driven. 

 On this account this mode of lodgment of teeth is 

 termed gomphosis. 



