MOLARS OF SECOND DENTITION PERMANENT MOLARS. 



37 



The external faces have two longitudinal gutters separated 

 by a ridge; the first molar has three gutters with two ridges; 

 the internal faces have two shallow gutters on the first molar 

 and one on each of the others, which is closer to the posterior 

 border of the teeth in the last ones. There is no neck or dis- 



FIG. 24. 



A, transverse section of the upper jaw, showing the left third temporary 

 molar and its relation to the permanent molar which replaces it. B, third perma- 

 nent molar, capped by the worn temporary molar. 



tinctive line (Fig. 24) separating the crown or free extremity 

 from the roots or imbedded extremity of the permanent molars. 

 The free extremity is triangular in the first and sixth teeth, and 

 quadrangular in the others. In the virgin tooth it has an ir- 

 regular surface resembling an Old English ^, with loops looking 



