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, a, 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.) 



