SERPENTES 



THE REPTILES OF 

 WESTERN NORTH AMERICA 



Suborder II. SERPENTES (Snakes) 

 Synopsis of Families 



. — Tail cylindrical or conical, not oar-shaped. 

 b. — Ventral scales less than twice as broad as dorsals. 



Plates on top of head not larger than those on bodyj 

 anus bordered in front by a single plate ; a small spine 

 at end of tail. 



Leptotyphlopidae. — p. 62+. 

 b'. — ^Ventral plates more than twice as broad as dorsal 

 scales. 

 c. — No rattle at end of tailj no pit between nostril and 

 eye. 

 d. — A small spur at each side of the anusj tail short 

 and truncate, or top of head with small scales; 

 pupil vertical. 



Boidae. — p. 630. 

 d". — No spur at side of anus; tail tapering; top of head 

 with large plates; pupil round or vertical. 

 e. — No enlarged fangs at front of mouth ; coloration, 

 if in rings, not red separated from black by 

 white (yellow). 



Colubridae. — p. 644. 

 e*. — A pair of large permanently erect fangs near 

 front of upper jaw; coloration, in rings, red 

 separated from black by white (yellow). 

 Elapidae.— p. 887. 

 c. — A horny rattle at end of •-■il: a pit between nostril 

 and eye; a pair of large erectile fangs; pupil vertical. 

 Crotalidae. — p. 893. 



