CHAPTER XIII. 



THE TEETH OF INSECTIYORA, CHIROPTEEA, AND PRIMATES. 



The insect! vora form rather a heterogeneous order of Mammals. 

 and embrace very various forms. All of them are of rather small 

 size, and some are very small indeed. Their diet consists for the 

 most part of insects, and their teeth are generally adapted for thi^ 

 by being furnished with many points. The best known animals in 

 the order are the Hedgehogs, the Shrews, and the Moles ; to these 

 are to be added the Galeopithecus, or ' Flying Lemur," and the 

 Macroscelidae (Elephant mice). Insectivora are more abundant in 

 Africa, Asia, and South America than in Europe. The Shrews 

 approximate in some measure towards the Rodents, and the Tupaia 

 is very lemurine in its characters. 



THE common English Hedgehog (Erinaceus) has the dental 

 formula 



.30 43 

 4c.pm.m-. 



In the upper jaw there is a wide interval between the 

 first pair of incisors, which are much the largest, and are 

 caniniform in shape. The next two teeth (incisors) are 

 quite small, and resemble premolars in their form. The 

 next tooth has two roots, and a crown with one cusp, and is 

 also like the premolars behind it. This tooth, the root 

 of which shows indications of division, is sometimes called 

 a canine, because it comes next behind the intermaxillary 

 suture ; behind this come two small premolars. 



The fourth upper premolar is totally different in size and 

 form from the third : its crown is large, squarish, and 



