160 PHYSIOLOGY AT THE FAKM. 



last of all, which are so much more voluminous, seven great 

 points, without counting points of smaller size. The farthest 

 back of these points is an odd one, and all are traversed by 

 longitudinal grooves, while the spaces between the great points 

 are occupied by smaller ones. 



In the pig there are thirty-two milk-teeth namely, twelve 

 incisors, four canine, and sixteen false or premolar teeth 

 equally divided between both jaws. Some division of opinion 

 exists as to the succession in which these appear. According 

 to Simonds, the pig is born with eight teeth namely, two 

 upper and two under middle incisors, and one canine on each 

 side of each jaw. By the age of one month the incisors have 

 increased to four in each jaw, while twelve premolar teeth have 

 come out namely, three on each side of each jaw. At three 

 months the outer incisor on each side of each jaw appears. 

 At six months the last premolar comes out, and the teeth of 

 the first set are now complete. 



About the age of nine months the outer incisors on each side 

 of each jaw drop, and are replaced by the corresponding per- 

 manent incisors this change being usually somewhat later in 

 the lower jaw than in the upper. Near the same age the milk 

 tusks or canines are exchanged for the corresponding per- 

 manent teeth. Between the age of one and that of two years 

 the middle incisors or pincers are shed and replaced. About 

 the same time a black circle appears at the base of each of the 

 canine teeth. Between one and two years of age the deciduous 

 or premolar teeth are shed, and replaced by permanent pre- 

 molars. The first and second true permanent molar teeth ap- 

 pear before the shedding of the milk teeth is over the first, 

 namely, at six or seven months of the pig's age ; the second, 

 at about ten months ; but the third does not come forth till 

 three years after birth. 



After three years the age of the boar may be computed by 



