THE POISONOUS SNAKES OF INDIA. 



1. 



4. 



Key to cUstinguish the Poisonous Snakes. 



Tail compressed (i.e., flattened like an Sea snakes 



eel's) (see Fig. lA). Snout and crown (29 species). 



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



Fig. 6). 



Tail round (see Fig. 1 C). 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). 



Tail round (see Fig. 1 0). 3rd supralabial 

 touching the nasal shield and the eye 

 (see Fig. 12).* 



Cobras and 

 coral snakes 

 (9 species), 

 (see p. 23.) 



Pit vipers 

 (13 species), 

 (see p. 39.) 



'o 

 o 



o 

 i3 

 o 



CO 



o 



Pitless 

 vipers 

 (6 species). 

 (see p. 54.) 



> 



ft 



J 



Tail round (see Fig. 1 C). A conspicuous 

 opening in the side of the face between 

 the eye and the nostril (see Fig. 24 B). 

 Vertebrals not enlarged, f 

 5. Tail round (see Fig. 1 C). Snout and 

 crown covered with small scales as on 

 back of body (see Fig. 37). Only part of 

 the last row of costals visible on either 

 side of the ventrals when the specimen 

 is laid on its back (see Fig. 5 and 

 contrast with Figs. 3 and 4). 



A specimen which cannot be brought into one of these five 

 groups is harmless, except Azemiops fece, which may be known from 

 all other snakes by having 1 7 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 Gallophis macclelUmdi, in which 

 the 3rd supralabial just failed to touch the nasals, and as the contact between 

 these shields in many of the species Gallophis and DoliopMs 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. 3rd 

 supralabial touching the eye, and a suture running from the nostril to the 2nd 

 supralabial- In the genus Naia the contact. of the 3rd 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 westerinarmi, 

 Ijut in this the vertebrals are enlarged. Only three examples are known, all from 

 Bengal (Rangpore, Purneah and Jalpaiguri). 



