THE TEETH 



437 



Of the upper incisors (Figs. 366, 367) the medial pair are the 

 larger, and are slightly in advance of the lateral pair. The crown is 

 compressed from before backward and presents a sharp transverse 

 cutting edge, which before the tooth is worn has three small cusps. 



FIG. 366. 



2 3 



FIG. 367. 



2 3 



UPPER AND LOWER PERMANENT TEETH. 

 EXTERIOR VIEW. 



1, first incisors; 2, canines; 3, first premolars; 

 4, middle molars. 



UPPER AND LOWER PERMANENT TEETH. 

 LATERAL VIEW. 



1, first incisors; 2, canines; 3, first premolars; 

 4, middle molars. 



The anterior surface is flattened ; the posterior surface is flat or con- 

 cave and sometimes presents a basal swelling which is connected with 

 the angles of the cutting edge by lateral ridges. The crown joins the 

 single fang without a marked cingulum or a decided neck. 



The lateral incisors differ from the medial incisors by their smaller 

 size, by the rounding of the lateral angle of the cutting edge of the 

 crown, and by the greater convexity of the outer surface. 



The lower incisors are smaller than the upper, and their fangs are 

 more strongly compressed from side to side. The crowns have no 

 distinct basal swellings on their posterior surfaces. The lateral pair 

 are slightly larger than the medial pair. 



The canines (Figs. 366, 367) have pointed crowns and longer 

 fangs. The outer surface of the crown is convex ; the inner surface 

 presents a vertical median ridge and two marginal ridges which meet 

 at a basal cin;ular swelling and limit two concave areas. The side of 



O O 



the cutting edge of the crown near the premolar is the longer. 



The crown of the lower canine is more obtuse than that of the 



