THE MOUTH 



479 



The formula for the temporary teeth is : 



/ 3 1 4\ 



I ( Di-Dc-Dp- I 



V 3 1 4/ 



= 32 



The upper incisors are small; they are separated from each other by spaces, 

 and from the canines by a larger interval. The first incisors are the largest; they 

 are flattened and strongly curved, and the crowns are convergent; they have no 



Fig. 413. — Sktjll of Pig about a Year and a Half Old, Sculptured to Show the Embedded Parts of the Teeth. 

 Il~3, Incisors; C, canines; Pl~4; premolars; Ml-3, molars. The third molar has not erupted and its roots are not 



yet formed. 



Cement Enamel Dentine 



distinct neck. The convex labial surface has an extensive covering of enamel, but 

 the latter covers only a small marginal area on the lingual surface. The second are 

 much shorter and are only slightly curved ; they have a short flattened crown and 

 a rounded root. The third incisors are much smaller, are 

 flattened laterally, and have three small eminences on the 

 crown. The lower incisors are almost horizontal and are 

 convergent and close together. The first and second are 

 about equal in size, are rod-like, very slightly curved, and 

 deeply implanted in the jaw. The labial surface is slightly 

 convex, the lingual concave and marked near its extremity 

 by a ridge. The third incisor is much shorter and is some- 

 what flattened; it has a short narrow crown and a distinct 

 neck. 



The canine teeth or tusks of the male are greatly de- 

 veloped and project out of the mouth. The upper canine of the boar may be three 

 or four inches (ca. 8 to 10 cm.) long. The crown is conical and is curved some- 

 what backward and outward; the embedded part is curved and has a large pulp 



Fig. 414. — Cross-section of 

 Lower Canine Tooth 

 OF Pig. 



c, Pulp cavity. 



