310 JOURNAL, BOMBAY NATURAL HISTORY SOCIETY, Vol. XV J I. 



Poison. — Nothing known. 



Dimensions. — It grows to 4 feet. 



Colour. — Head and neck black except for a yellowish oblique occipi- 

 tal streak. Dorsally purplish- brown, reddish-brown, or red, with 3 or 

 5 longitudinal series of spots which in some specimens are confluent, 

 and form lines. Belly uniform red. 



Group 4. — The Pit Vipers. 



Identification. — (1) Tail round. (2) A conspicuous opening in the 

 side of the face between the eye and the nostril (the loreal pit) 

 (see Fig. 24 B). 



This very distinctive character is peculiar to this subfamily of vipers. 

 In spite of the fact that many members of this subfamily (Crotalinse) 

 attain formidable proportions, and almost all are endowed with remark- 

 ably large poison fangs, the numerous accounts of bites inflicted by 

 them to be found in scientific and other journals, concur in showing 

 that death is an exceedingly rare event. My own experience supported 

 by that of many of my friends, who have favoured me with letters 

 on this subject, entirely confirms the foregoing. A painful and 

 swollen condition locally and a very variable degree of constitutional 

 disturbance lasting in some instances for weeks passes on to complete 

 recovery. 



These snakes are nearly all exclusively confined to hilly regions at 

 altitudes ranging between 1,500 to 10,000 feet. The characters of the 

 shields, and scales upon which the classification of nearly allied 

 ophidian forms is so largely based, are subject to very great inconstancy 

 in the members of this group, so much so that it is with the greatest 

 difficulty one can frame a lucid and really practical key to identify the 

 various species. I have, however, examined and re-examined most 

 critically all the specimens in the British Museum, and have only made 

 allusion to those peculiarities which are most constant, and which seem 

 to me of real practical use in identification. 



Key for Identification of Pit- Vipers. 

 HEAD WITH LARGE SHIELDS (see Figs. 24 and 26). 



Scales midbody in '21 or 23 rows (see Fig. 7) ... Ancistrodon himalayanus. 



Scales midbody in 17 rows „ hypnale. 



Scales midbody in 15 or 14 rows Lachesit maerolepis. 



HEAD COVERED WITH SMALL SCALES (see 

 Kg. 27). 



