4 INTRODUCTION 



even they may sometimes feel embarrassed, unless 

 the dentition be examined ; the mistakes which 

 have occasionally been made by some experienced 

 herpetologists are proof sufficient of the fallacy of 

 external characters for this purpose. 



The Ophidia are divided into nine families, the 

 first, third, seventh, and ninth of which have repre- 

 sentatives in Europe : 



I. No transverse (ectopterygoid) bone ; pterygoid 

 not extending to quadrate or mandible ; no supra- 

 temporal ; nasals in contact with prefrontals ; 

 coronoid present ; vestiges of pelvis. 



Maxillary loosely attached to lower surface of 

 cranium, toothed; lower jaw edentulous; a single 

 pelvic bone i. Typhlopid^. 



Maxillary bordering mouth, forming a suture with 

 premaxillary, prefrontal, and frontal, toothless ; 

 pubis and ischium present, latter forming a sym- 

 physis 2. Glauconiid^e. 



II. Transverse bone present ; both jaws toothed. 



A . Coronoid present ; nasals in contact with pre- 

 frontals, 

 i. Vestiges of pelvis ; supratemporal present. 

 Supratemporal large, suspending quadrate 



3. BoiDiE. 



(Subfamilies : Pythonincz, Boince.) 

 Supratemporal small, intercalated in the cranial wall 



4. Ilysiidjs. 



