THE POISONOUS SNAKES OF INDIA. 



Key to distinguish the Poisonous Snakes. 



1. Tail compressed {i.e., flattened like an eel's) Sea snakes 



(see Fig. lA). Snout and crown covered (29 species), 

 with large plate-like shields (see Fig. 6). (see p. 8.) 



2. Tail round (see Fig. 1 H). Median row of Kraits (11 



scales down the back distinctly enlarged species). 



(see Fig. 7). Only 4 infralabial shields, (see p. 9.) ^ 



the 4th largest (see I to IV, Fig. 8). | 



1 



3. Tail round [see Fig. 1 C). 3rd supralabial Cobras and 



touching the nasal shield and the eye coral snakes 

 {see Fig. 12).* (9 species). 



(see p. 25). J 



4. Tail round (see Fig. 1 C). A conspicuous Fit vipers 1 



opening in the side of the face between (13 species). 

 the eye and the nostril {see Fig. 24B). (see p. 41.) 



Vertebrals not enlarged, t 



Tail round {see Fig. 1 C). Snout and Pitless 

 crown covered with small scales as on vipers 

 back of body (see Fig. 37). Only part of (5 species), 

 the last row of costals visible on either {see p. 57.) 

 side of the ventrals when the specimen 

 is laid on its back {see Fig. 5 and 

 contrast with Figs. 3 and 4). 



Ph 



o 

 o 

 'o 



J 



A specimen which cannot be brought into one of these five groups 

 is harmless, except Azemiops fecc, which may be known from all 

 other snakes by having 17 rows of scales in midbody, and 6 supralabials, 

 the third of which only touches the eye. 



* Since writing this I have seen two specimens of Callopliis macdellandl, in which the 

 3rd supralabial just failed to touch the nasals, and ae the contact between these shields in 

 many of the species ra//op/i« and /)o^»o/;//i.< is often very small, it is probable that the 

 same departure from the normal may be met with in certain individuals of other species of 

 these genera. For this reason when the 3rd just fails to touch the nasal, I give an alternative 

 method of diagnosis as follows. B'd supralabial touching the eye. and a B"tiire running 

 from the nostril to the 2nd supralabial. In the genus Naia th^ contact of the Srd supralabial 

 with the nasal is invariable, and this alternative rule therefore is not intended to apply. 



t One harmless snake has a loreal pit, the very rare Elachistodon westermanni, but in 

 this the vertebrals are enlarged. Only two examples are known, both from Bengal 

 (Knngpore and Purneah). 



