1116 



SPLANCHNOLOGY 



The crown is directed vertically, and is chisel-shaped, being bevelled at the expense 

 of its lingual surface, so as to present a sharp horizontal cutting edge, which, 

 before being subjected to attrition, presents three small prominent points separated 

 by two slight notches. It is convex, smooth, and highly polished on its labial 

 surface; concave on its lingual surface, where, in the teeth of the upper arch, it is 

 frequently marked by an inverted V-shaped eminence, situated near the gum. 

 This is known as the basal ridge or cingulum. The neck is constricted. The root 

 is long, single, conical, transversely flattened, thicker in front than behind, and 

 slightly grooved on either side in the longitudinal direction. 



FIG. 1001. Front view of the skull shown in Fig. 1000. Note the relation of the permanent incisors and cuspids to each 

 other and the roots of the temporary teeth. (Noyes.) 



The upper incisors are larger and stronger than the lower, and are directed 

 obliquely downward and forward. The central ones are larger than the lateral, 

 and their roots are more rounded. 



The lower incisors are smaller than the upper: the central ones are smaller than 

 the lateral, and are the smallest of all the incisors. They are placed vertically 

 and are somewhat bevelled in front, where they have been worn down by contact 

 with the overlapping edge of the upper teeth. The cingulum is absent. 



The Canine Teeth (denies canini) are four in number, two in the upper, and two 

 in the lower arch, one being placed laterally to each lateral incisor. They are larger 

 and stronger than the incisors, and their roots sink deeply into the bones, and 

 cause well-marked prominences upon the surface. 



