THE TEETH OF PRIMATES. 405 



have grown to an inordinate length, and have diverged from 

 one another, it will serve to show the rodent-like aspect of 

 its mouth. 



Although, functionally, its teeth are those of a rodent, 

 yet despite this adaptive resemblance, the milk dentition 



FIG. 177 ('). 



retains certain characters which indicate the lemurine origin 

 of the creature. 



In the upper jaw the milk dentition consists of two small 

 incisors, a canine and three molars ; in the lower jaw of two 

 small incisors and two small molars ; it is said that in an 

 early stage a third milk incisor is to be found. 



The permanent incisors push their way up between the 

 first and second milk incisors ; at a certain stage all three 



( ! ) Aye- Aye (Cheiromys), which died in the Zoological Gardens (after 

 Dr. Murie). The upper incisors, from want of sufficient use, have grown 

 long and diverged from the middle line. 



