412 



DIGESTIVE SYSTEM OF THE PIG 



The formula for the temporary teeth is: 



/ 3 1 4\ 



I Di - Dc - Dp - I 

 V 3 1 4/ 



Dp - ) = 32 



3 1 4, 



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, are 

 convergent, and have no distinct neck. The second are narrower and somewhat 

 smaller. The third (corner) 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 to- 

 gether. The first and second are about equal in size, prismatic, and deeph' im- 



FiG. 308. — Skuli. of Pic about a Year and a Half Old, Sculptttred to Show the Embedded Parts of 



THE Te?;th. 

 Il-S, Incisors; C, canines; Pl-4, premolars; Ml-.i, molars. 



planted in the jaw. The la])ial surface is slightly conv(>x, the lingual concave and 

 marked near its extremity by a ridge. The third incisor is nmch smaller and 

 has a short narrow crown and a distinct neck. 



The canine teeth or tusks of the male are greatly developed and project out 

 of the mouth. The upper canine of the boar may be about three or four inches 

 (ca. 8 to 10 cm.) long. The crown is conical and is curved somewhat backward 

 and outward; the embedded part is curved and has a large pulp cavity.' 

 The lower canine may reach a length of eight inches or more (ca. 20 cm.) ; the crown 

 is prismatic and is curvefl backward and outward in front of the upper one, so that 

 the friction between the two keeps a sharp etlge on the lower tootii. In the sow 

 they arc much smaller. 



The cheek teeth increase in size from before backward. Th(>v have (with 



^ The ciinincs of the pig are "perniancnt pulp" teeth and tliercfore capable of continued 

 growth, and are without roots in the strict sense. 



