VE TERINAR T DENTAL S URGER I. 251 



but they are visible under the gum. The centrals 

 make their appearance first, and are rapidly suc- 

 ceeded by the other pairs in their order, so that by 

 the fourth week they are fully developed. At 

 eighteen months the central incisors are replaced by 

 permanent teeth, which are up and in wear at two 

 years old. 



At two years the first intermediate (internal lat- 

 eral) are shed and permanent teeth take their place. 

 These are up and in wear by the third year. 



From three years to three years and two months, 

 the second intermediate (external lateral) are shed 

 and replaced by permanent teeth, which are up and 

 in wear by the fourth year. 



From three years and nine months to four years 

 and three months, the corner incisors are shed and 

 permanent teeth appear, which are up and in wear 

 by the fifth year. 



The changes which take place in the dentition of 

 the molar teeth are relatively the same as in the ox. 

 DENTITION IN THE PIG. 



The pig is born with eight temporary teeth, the 

 corner incisors and the tusks. At three to four 

 weeks the first incisors make their appearance, and 

 at eight weeks the second incisors are cut. At one 

 month the first four molars are cut, and are tem- 

 porary, with the exception of the first, which is per- 

 manent. At nine months to one year the corner 



