THE DEVELOPMENT OF THE TEETH. 



127. 



alteration in position takes place ; instead of preserving a 

 vertical position, they become recumbent, so that the form- 

 ing tooth lies more or less parallel with the long axis of the 

 jaw. The utility of such an arrangement is obvious : were 



....I 



the tooth to remain erect after it has attained to some little 

 length, its point would probably be forced through the 

 mucous membrane when the mouth was put upon the 

 stretch ; but while it lies nearly parallel with the jaw no- 

 such accident can occur. 



The tooth does not resume the upright position until it 

 finally moves into its place upon the summit of the bone. 



( J ) Developing teeth of a Snake. /. Oral epithelium, e. Neck of the 

 enamel organs, b. Dentine pulp. c. Enamel cells, d. Dentine. 1, 2. 

 Very young germs. 3, 4. Older germs. 



