CH. V.] 



1'HB TEETJi 



The temporary or milk-teeth have only a very limited term of 

 existence. 



They are ten in number in each jaw, namely, on either side from 

 the middle line two incisors, one canine, and two deciduous molars, 

 and are replaced by ten permanent teeth. The number of permanent 



FIG. 92. Normal well-formed jaws, from which the alveolar plate has been in great part removed, so 

 as to expose the developing permanent teeth in their crypts in the jaws. (Tomes.) 



teeth in each jaw is, however, increased to sixteen by the develop- 

 ment of three molars on each side of the jaw, which are called the 

 permanent or true molars. 



The following formula shows, at a glance, the comparative arrange- 

 ment and number of the temporary and permanent teeth : 



MOLARS. 



2 



CANINE. 

 1 



Temporary Teeth. 



MIDDLE LINE OF JAW. 



INCISORS. 



2 

 2 



INCISORS. 



2 



CANINE. 

 1 



= 10 



:20 



TRUE 

 MOLARS. 



3 

 3 



BICUSPIDS 

 OR PRE- 

 MOLARS. 



Permanent Teeth. 

 MIDDLE LINE OF JAW. 



CANINE. INCISORS. 



INCISORS. CANINE. 



BICUSPIDS 

 OR PRE- 

 MOLARS. 



TRUE 

 MOLARS. 



From this formula it will be seen that the two bicuspid or pre- 

 molar teeth in the adult are the successors of the two deciduous 



