IRREGULARITIES IN NUMBER AUGMENTATION. 



125 



(a) directed transversely and held in place below the incisive 

 foramen by a bony bridge. 



Figures 128 and 128a show a pincher tooth similarly 

 deflected. 



All these teeth are of second dentition. 



Supernumerary teeth of the lower jaw are less common 

 than in the upper one ; they sometimes, however, occur. The 

 presence of supernumerary teeth rarely modifies the wearing of 

 the others in the marking of age. Supernumerary teeth are 

 usually firmly held in their alveolar cavities, and rarely alter 

 the shape of the arch of the incisors except when milk-teeth are 

 still remaining, with which they should not be confounded. 



Figures 129 and 130 show an upper jaw from the collec- 

 tion of Dr. J. W. Gadsden, of Philadelphia, in which will be 

 seen two supernumerary intermediate teeth, a right-hand super- 

 numerary corner tooth, and the corner teeth of first dentition 

 still remaining. 



Fia. 130. 



