R N L POSO ho T 



W 5 



W. S(uavt (Vavuer' 



Plate 1. Fig. 1. Head of venomous snake (Crotalidae), lateral and dorsal view. 

 Fig. 2. Head of non-poisonous snake (Colubndae), lateral, ventral and dorsal view. 

 Fig. 3. Section of body showing keeled scales. Fig. 4. Section of body showing smoo'.h 

 scales and scale rows. Fig. 5. Ventral surface showing rapidly tapering tail as seen 

 in female snakes. Fig. 6. Ventral surface showing slowly tapering tail as seen in male 

 snakes. 



AD — Anal plate divided. AS — Anal plate single. C — Canthal. CS — ^Chin shields. 

 F — Frontal. I — Internasal. L — Loreal. LL — Lower labials. M — Mental. N — Nasal. 

 P— Parietal. PF— Prefrontal. PO— Preocular. Pt.— Pit. PtO— Postocular. R— Rostral. 

 S — Subcaudals. SO — Supraocular. T — Temporal. UL — Upper labials. V — Ventrals. 



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