SYNOPSIS OF THE REPTILIA. 34i5 



Order III. ELANOSAURES. Fish Lizards. 

 Body lacertiform ; feet fin-shaped ; jaws exceedingly long. 



Flesioscmres. Neck excessively long ; jaws short. 

 Ichthyosaures. Jaws very long ; neck short. 



Saiirocephalus. Incisors with a hole on the inner edge of the alocola. 

 Pterodactylus. Jaws excessively long ; feet furnished with toes, the 

 anterior wing-like. 



OnDER IV. OPHIDES. The Serpents. 

 Feet none. 



Family 1. HYDROPHIDiE. Water Serpents. 



Body and tail compressed ; nostrils operculated ; anal spurs 

 none ; upper jaw with poisonous fangs. 



Hydrus. Head small, not enlarged behind ; plaited. 

 Pelamys. Head enlai-ged behind ; scales small, hexagonal. 

 Chersydrus. Head and body with small carinated scales. 

 AcHRocoRDus. Like the last, but the tail is not compressed. 

 Herpeton". Head with two soft scaly tentacula. 

 PsEUDOBOA. Head enlarged behind, plaited ; back carinated. 



Family 2. CROTALID^. Poisonous Serpents. 

 Upper jaw with poisonous fangs ; tail cylindrical. 



Crotalus. Tail ending in a rattle ; scales similar on the head 

 and back. 

 Caudisona. Like the last, but with plates on the head. 



TisiPHONus. Tail ending in a spine or sting ; head with plates. 



Craspedocephalus. Head scaled ; sub- caudal plates double. 



CoPHiAS Merr. Head broad behind, large, scaled ; tail simple. 

 Trigonocephalus. Head with plates. 



Cerastes. Head broad, covered with scales or plates ; no de- 

 pression behind the nostrils. 

 Cerastes. Scales of the head and back similar ; nostrils large, simple. 

 Berus. Head with granular scales ; sub-caudal plates double. 

 Echis. Head with small scales ; sub-caudal plates single. 

 Acanthopes. Tail with a hook ; front scaled. 



Naia. Head with large regular plaits. 



Naia. Neck capable of being dilated ; head narrow. 

 Lepidon. Neck not expansive ; head broad. 

 Elaps. Head narrow ; dorsal scales equal. , 



Platurus. Body cylindrical ; tail compressed. 



Trimesurus. Head distinct ; tail conical ; caudal plates double and 



single. 

 Oplocephalus. Like the last, but the caudal plates simple. 



