MASTICATION. 



259 



The following figures, from the " Encyclopadie der gessammten 

 Thierheilkunde," indicate the changes occurring with age in the incisor 

 teeth of cattle (Pig. 104). 



Newborn. 8 Days. 4 Weeks. 



1 Year. 



2 Years. 



2% Years. 



K 



12 Years. 14 Years. 16 Years. 18 Years. 20 Years. 



Fig. 104.— Changes from Age in the Incisor Teeth of the Ox. (Wilckens.) 



Dentition of Sheep. — In the sheep it is by the displacement of tem- 

 porary and eruption of the permanent teeth that the age of the animal 

 is determined. 



Table op Early Dentition. 



Table of Late Dentition. 



Years. 



Mos. 



No. of Teeth. 



Years. 



11 OS. 



No. of Teeth. 



1 



1 

 2 

 3 







6 

 3 

 



Central pair of temporary 

 incisors replaced by per- 

 manent. 



Second 



Third 



Fourth 



1 



2 

 2 



3 



4 





 9 

 6 



Two permanent incisors. 



Four " 



Six 

 Eight 



