THE TEETH OF MAMMALS 175 



the rounded arch of man. The skull is small, and 

 the teeth and jaws are still prominent and prog- 

 nathous. The Lemurs are the lowest of the Quad- 

 rumana, and connect that order with the lower 

 mammals in many features of structure. They 

 have the formula, — 



. 2-2 1-1 3-3 3-3 Qa 



U £3 C Ti P ' m - 3^ m ' 3^ = 36 * 



The upper incisors are small (Fig. 74), and are 

 separated from each other by wide spaces. The 



Fig. 74. — Teeth of Ruffed Lemur (Lemur varia). 



lower incisors project straight forward and inter- 

 digitate with the upper, passing into the inter- 

 dental spaces. This enables them to cut up the 

 tender shoots of bamboo, twigs, grass, etc., on 

 which they feed, with facility. The upper canine 

 is large and pointed, with sharp edges. The 

 lower canine is like the incisors in form and 

 ranges forward with them. The premolars are 

 sub-compressed, and have long, sharp cusps. The 

 first upper premolar is large and caniniform. 



