TEETH IN THE OX. 85 



the second molar of the first set gives place to the second 

 permanent molar, which is one of the false molars. In the 

 course of the fourth year the third molar of the first set makes 

 way for the third permanent molar, the farthest back of the 

 false molars ; while the third milk incisor gives place, about 

 the same period, to the third permanent incisor. In the latter 

 part of the fourth year, or in the beginning of the fifth year, 

 the sixth molar, on each side of each jaw, makes its appear- 

 ance that is, the backmost tooth of all. The teeth which 

 complete the second dentition are the two outer of the eight 

 incisors, which replace the corresponding incisors of the first 

 set before the end of the fifth year. 



Each tooth in the ox, as in other common mammals, consists 

 of a crown, a neck, and a fang or fangs. 



The substances composing the teeth of the ox are the same 

 as those which enter into the teeth of the horse, and into the 

 teeth of ruminant animals in general namely, enamel, cement 

 or the petrous crust, and dentine. The arrangement of these 

 several substances in the teeth of the ox so much resembles 

 that already described in the teeth of the horse, that it seems 

 unnecessary to do more here than to refer to what has been 

 said under the head of structure in the teeth of the horse, p. 

 13. The same may be said of almost all the other important 

 particulars respecting the teeth of the ox. 



The bones which form the roof of the mouth are, as in the 

 horse, the intermaxillary bone, the upper jaw-bone, and the 

 palatine plates of the palate-bones. The intermaxillary bone, 

 as in the horse, is behind the upper lip, but does not, as in the 

 horse, exhibit any incisor teeth or any tushes. As in the horse, 

 the intermaxillary is made a pair of bones, under the name 

 of anterior maxillaries. The upper jaw-bone, called also the 

 superior maxillary, is, as in the horse, of great size. It enters 

 into the formation of the orbit of the eye, and into the nose, 



