PLATE II. 



DISSECTED SKULLS SHOWING THE DEVELOPMENT OF THE TEETH 

 (Noyes). 



1. Skull at nine months, central incisoFS just erupted, laterals not yet 

 through the gum. The root of the central about half formed. The 

 lower first and second temporary molars seen in their crypts. The crypt 

 for the lower first permanent molar shown, but the developing tooth has 

 dropped out of it. The upper temporary cuspid and first and second 

 molars are seen in their crypts. Notice the straightness of the lower jaw. 



2. Skull at one year. Two incisors in each jaw are erupted. The 

 first molars are just starting. Notice the formation of the root of the 

 lower temporary molars just beginning. Also notice the first permanent 

 molar in its crypt with half of the crown formed. 



3. Skull in the second year. The temporary first molar dnd cuspid 

 partly erupted. Notice the development of their roots. Notice the per- 

 manent cuspid above and me first molar below in their crypts. 



4. Skull in fourth year. Complete temporary dentition. Notice 

 the upper central, lateral cuspid and bicuspid in their crypts; the 

 lower incisors, cuspid, first bicuspid, and first permanent molar. 



5. Skull in sixth year. Complete temporary dentition with the 

 first permanent molar in place. The lower central incisors have just 

 beenjost and the permanent ones are just coming through the gum. The 

 cuspids, bicuspids and second molar are seen in their crypts. 



6. The left side of the same skull as No. 5. Notice the extent to 

 which the roots of the first permanent molar are developed. 



7. Front view of the same skull as No. 6. Notice the position of the 

 incisors and cuspids in their crypts. 



8. Skull in seventh year. The toothless age. Upper incisors lost 

 and the permanent ones not erupted. One lower incisor in place. First 

 permanent molar in place, but the roots not fully formed. Crown of the 

 second permanent molar seen in its crypt 



