54 INTRODUCTION 



With the exception of the worm-like Typhlopidse, 

 which are provided with a few teeth in the upper jaw 

 only, European snakes have teeth on the maxillary, 

 palatine, pterygoid, and dentary bones. Unless the 

 maxillary be strongly abbreviated and modified in 

 connexion with the poison apparatus, as in the 

 Viperidae, the teeth in the jaws as well as on the 

 palate form single longitudinal series ; they are 

 elongate, conical, with or without a sharp posterior 

 edge, more or less recurved, acutely pointed, some- 

 times needle-like, and directed backwards, as behoves 

 their function, which, in addition to attack and 

 defence, is to prevent the retrogression of the prey 

 in the act of prehension and deglutition. A notable 

 exception occurs in the genus Iguanognathus, from 

 Sumatra, all the teeth having spatulate crowns 

 ribbed along the outer side. Unfortunately, nothing 

 is known as to the food of this remarkable snake. 

 The teeth are coated with a thin layer of enamel. It 

 was held, for a time, that the glossy outer coating was 

 only due to a denser structure of the dentine. As in 

 all living Reptiles with the exception of the Crocodiles, 

 the teeth are not implanted in true sockets, but 

 simply ankylosed to the bone on which, when de- 

 tached, their slightly enlarged base, or rather the 

 bony tissue on which it rests, leaves a shallow im- 

 pression, or pseudo-socket. In the process of biting 

 or feeding, some of the teeth are frequently lost, and 

 are readily replaced by others lying in reserve in the 



