of the Animals of the Farm. 



59 



development, and afford valuable evidence in cases where an 

 opinion cannot be formed from an inspection of the incisors alone. 



The next change in the dentition is the final one, and occurs 

 between the age of seventeen and eighteen months. At this 

 period the sixth molar, a permanent tooth, is cut ; and in 

 forward animals the lateral temporary incisors are changed for 

 permanent teeth. In many instances the temporary lateral 

 teeth remain up to the age of eighteen months, although they 

 are in such cases quite loose ; and very often the permanent 

 teeth are cutting through the gum below or by the side of them ; 

 in other instances one lateral is found to be fully up and nearly 

 level with the centrals, while the other is just pushing through 

 the gum. The sixth molar is also fairly up, but the posterior 

 part of its crown is not quite clear from the gum. 



These changes complete the permanent dentition of the pig, 

 and there are no indications of the age afforded by the teeth 



Fig. 59. — Molars of Pig at eighteen months, sixth Molar well U2X 



after this period, excepting such as depend on the growth and 

 wear of the organs. 



In the above illustration (Fig. 59) the sixth molar is shown 

 as it appears at the completion of the age of eighteen months. 



It is very important that the examiner should exercise the 

 greatest care in the inspection of the teeth of pigs which are 

 exhiljited in the class above twelve and not exceeding eighteen 

 months old. Animals are entered at various ages from twelve 

 to eighteen months ; it is necessary, therefore, in this class to 

 note the condition of the central incisors and the anterior molars, 

 as well as that of the lateral incisors and the sixth molar. In 

 the next drawing (Fig. 60, p. 60) the full development of the 

 lateral permanent incisors is shown. This state of dentition, it 

 may be remarked, is indicative of a year and eight months. 



At the'age of two years the lateral permanent incisors are 

 quite level with the centrals and are worn on their edges, the 



