SKELETON 



45 



The principal modifications of the skull in the 

 European genera may be contrasted as in the 

 following synopsis : 



I. Quadrate articulating with the cranium, supra- 

 temporal absent; mandible much shorter than the 

 skull, with coronoid bone ; maxillary small, on 



-an 



Fig. 6 — Skull of Tropidonotus natrix. (From British Museum 



Catalogue of Snakes) 



Lettering of the bones as in Fig. 3 



lower aspect of cranium ; pterygoids not extend- 

 ing to quadrate ; nasals forming long sutures with 



the premaxillary, prefrontals, and frontal 



Typhlops. 



II. Quadrate suspended from the supratemporal ; 

 mandible at least as long as the skull ; pterygoids 

 extending to quadrate or mandible. 



