168 



AGE OF THE DOMESTIC ANIMALS. 



The permanent corner teeth have just replaced the tem- 

 porary ones, and are still in an oblique position, not having 

 completely emerged from the gum. 



Fig. 165. 

 Four years. «, external face. 6, internal face. 



FOURTH PERIOD LEVELING OF THE PERMANENT TEETH. 



At five years the pinchers have commenced to level. 



At six years the pinchers are leveled, both pairs of inter- 

 mediate teeth are nearly so, and the corner teeth are somewhat 

 worn. (Fig. 166, a.) 



