of the Animals of the Farm. 45 



from each otlier year by year, and the worn surface much broader, 

 as seen in the illustration opposite (Fig, 40), of the mouth of an 

 ox at the age of ten years. 



It will be seen that the characteristics of age are well 

 exhibited in the above. But it is also evident that the changes 

 in the teeth of the ox resulting from wear are not, as in the 

 teeth of the horse, of so definite a character as to enable the 

 expert to give an opinion up to an advanced period of the 

 animal's life. 



Dentition of the Sheep. 



The terms which are applied to the teeth of the ox for the 

 purpose of description may be used in regard to the teeth of the 

 sheep. Eight incisors, central, lateral, middle, and corner teeth, 

 are found in front of the lower jaw only, the corresponding part 

 of the upper jaw being provided with an elastic pad, as in the 

 ox. Molar teeth are designated by numbers, to indicate their 

 position, and for the purpose of judging the age. These teeth 



Fig. 41. — Incisors of Lamb at hirth. 



in the sheep may be described as corresponding to the teeth of 

 the ox in all general points, except in regard to their size. 

 At hirth, the arrangement of the incisor teeth of the lamb is 

 peculiar, as shown in Fig. 4 1 , 



Generally the whole temporary set of teeth may be recog- 

 nised, but only in outline, as they are nearly covered with the 

 gum. The central incisors are most advanced, and next in 

 order come the laterals, leaving the middle and corner teeth 

 considerably below them. Very often the catting edges of the 

 front and third pairs of teeth are through the gum. All these 

 peculiarities are seen in the illustration, which may be accepted 

 as a representation of the ordinary appearance of the teeth of the 

 lamb at birth. 



By the end oi t]iQ fourth ueek all the temporary teeth, eight 

 incisors, and three molars on each side of the upper and lower 

 jaws, are well up. : 



