2 14 Cj-ame of Europe, W. & N. Asia & America 



a difference between the two latter in this respect, and since domestication 

 nii"ht also have affected the period ot tooth-change, he was somewhat 

 sceptical as to the value of evidence of this nature. It appears, however, 

 that it may he approximately relied upon. 



Towards the close of its second year the sheep acquires the full 

 number of its lower teeth, that is to say, tour pairs of front ones and 

 six pairs of cheek-teeth, or grinders. At this period, however, the 

 first three pairs of grinders belong to the " baby," or milk set, and 

 it is not till some time in the third year that these give place to 

 their permanent successors. These permanent grinders are alwavs of 

 simpler structure than tlieir predecessors, from which thev mav also be 

 distinguished by the circumstance that their summits are less, instead 

 of more, worn than those of the three permanent grinders behind 

 them. 



But at the period of completion of the permanent series of grinders the 

 two outer pairs of lower front teeth still belong to the milk set, and it is 

 not till the fourth year that the outer pair but one of these are replaced by 

 their permanent successors, while the replacement ot the outermost pair does 

 not take place till the fifth year, when the entire dentition is complete. 

 Whether the two outer pairs ut lower front teeth belong to the milk or the 

 permanent set can be ascertained not only by their size, but also by the 

 fact that if they belong to the latter thev will be less worn than the 

 central pair, while if thev are of the milk set they will be more worn than 

 the latter. Although in the ox the outer pair of lower front teeth are 

 changed somewhat before the fifth year, it appears from a paper published 

 bv Dr. B. Nitsche, in vol. ix. of the German sporting periodical entitled 

 Deutsche II 'Jugcr-Zeitung, that in the wild chamois of the Alps the dates of 

 the various tooth- changes are much the same as in the sheep ; the 

 completion of the process not being attained till the fifth vear. It mav, 

 therefore, be presumed that a practically similar state of atlairs obtains 



