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 
Fic. 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, 
