THE SUBCLASS PARAPSIDA 277 



Uppermost Cretaceous. ? Coniophis Marsh, North America. 

 Eocene. ? Helagras Cope, North America. 

 Oligocene. N eurodromicus Cope,. North America. 

 Miocene. Viper a Laurenti, Germany. 

 Pleistocene. Crotalus Linne, North America. 



Family Elapidae. Ectopterygoids present. Maxillae horizontal, 

 not erectile, their anterior teeth deeply grooved or hollowed. Caudal 

 hypophyses bifid. Laophis, Salonica. 



This family of highly poisonous snakes, in its wider sense including 

 the cobras, sea snakes, and the coral snakes of the southern United 

 States, comprises nearly two hundred living species. They are prac- 

 tically unknown as fossils. Cobras (Naja Laurenti) have been re- 

 ported from the Pleistocene of France, but doubtfully. 



Family Colubridae. Ectopterygoid present, the coronoid ab- 

 sent. Maxillae horizontal, with solid teeth. Tabular present. Post- 

 orbital not produced forward. 



This family of harmless snakes includes more than half of all living 

 species, none attaining a size of more than seven or eight feet. Their 

 distribution is world-wide. 



Miocene. Elaphis Aldrich, Tamnophis Rochebrune, Fylemophis 

 Rochebrune, Periops Wagler, Europe. 



Pleistocene. Coluber Linne, Europe and North America [ =] Bas- 

 canion Baird and Gerard, North America. 



