114 



COLUBRID^. 



Family COLUBRID^E. 



Facial bones moveable ; prsefi'ontal not in contact with nasal ; 

 transpalatiue present ; pterygoid extending to mandible or quad- 

 rate ; siipratemporal present, nsually attached scale-like to the 

 skull and suspending quadrate ; iiiaxiliary horizontal, not moveable 

 perpendicularly to the transpalatiue; both jaws toothed; lower jaw 

 without coronoid bone. 



pnv 



Pig. 37. — Skull of Tropidonotus 2nscator, 



Divided into three parallel series and six subfamilies : — 



Series A. Agltpha. — All the teeth solid, not grooved. Harmless. 

 Subfam. AcrocJiordi7ice. — Postfrontal bone produced over the 



supraorbital region ; scales not imbricate. Thoroughly 



aquatic. 

 Subfam. Colubrince. — Postfrontal bone not produced over the 



supraorbital region ; scales imbricate. Aquatic, terrestrial, 



or arboreal. 



Series B. Opisthoglypha. — Only one or more of the posterior 

 maxillary teeth grooved. More or less poisonous. 



Subfam. Homalopsince. — Nostrils valvular, on upper surface of 

 snout. Thoroughly aquatic. 



Subfam. Dij-fsadomorpJiina'. — Nostrils lateral. Terrestrial or 

 arboreal. 



