II 



Oculars one and three. Brown with three yellow 

 stripes. Lateral stripe on second and third rows of 

 scales. Form stout T. sirtalis. 



Genus Natrix. 

 Anterior and posterior oculars present. Two nasals ; 

 one loral. Scales carinated. Anal plate divided. 



One anterior and three posterior oculars. Brown 

 with darker irregular transverse bands ; beneath, 

 white spotted with red . N. fasciata sipedon. 



Genus Storeria. 

 Size small. Two nasals. Loral absent. Scales carinated. 

 One preocular. Brown above, pinkish white beneath. 



, . . vS. dekayi. 



Two preoculars. Brown above, bright red beneath. 

 S. occipitomaculata. 



Family Crotalidae.* 



Head with a deep pit between the eye and nostril. 

 Upper jaw with two long erectile poison fangs. 



Synopsis of Genera and Species. 



Genus Agkistrodon. 

 Head with nine plates above. Tail ending in a horny 

 spine. Scales carinated. Urosteges entire. 



Light brown with reddish-brown transverse blotches, 

 which are widest laterally. Labials not entering 

 orbit A . contortrix. 



Genus Crotalus. 

 Head with small scales between the superciliaries and 

 posteriorly. Tail ending in a rattle. Urosteges entire. 



Light brown, with dark transverse dorsal bands. 

 Tail black . C. Jiorridns. 



*The two local species have the subcaudal scuta in one row. All the species 

 of the family have an elliptical pupil; this at once makes it easy to distin- 

 guish the local Colubridoe from the venomous species, as the former have a 

 round pupil and the subcaudal scuta bifid. 



