ON THE COMMON INDIAN SNAKES. 547 



Identification. —Attention must be directed to the following. The 

 scales are in 21 rows anteriorly, i.e., two heads lengths behind the 

 head, 21 in mid body, and 15 posteriorly, i.e., two heads lengths before 

 the vent. This arrangement is only to be found in certain species 

 of this genus and some pitvipers, Laches is gramineus, etc. The 

 enlarged plates on the head will eliminate all the vipers which share 

 the scale peculiarities just noted, and thin the diagnosis down to 5 

 species of D ipsadomo rphus ,* viz., trigonatus, hexagonotus, ceylonensis, 

 cyaneus and multifasciatus. Trigonatvs has the vertebral row of scales 

 feebly enlarged in the middle of the body, and fewer subcaudal shields, 

 viz., 75 to 92. In the rest, excepting multifasciatus, the vertebrals are 

 as broad as long in the middle of the body, and in multifasciatus the 

 subcaudals vary from 96 to 114. 



To sum up diagnosis rests on — 



(1) The scales being 21, 21, 15. 



(2) The head covered with large plares. 



(3) The feeble development of the vertebrals in midbody. 

 (1) The subcaudals 75 to 92. 



Disposition. — This with others of its genus is one of the most 

 intrepid snakes 1 know. Often with no further provocation than 

 being suddenly disturbed or confronted, it will assume an attitude 

 of defiance and with little hesitation boldly act on the offensive. 

 The attitude it adopts at these times is very characteristic. The head 

 and forebody are erected well off the ground, and the latter thrown 

 into loops of which two overlapping one another are thrown to one 

 side and one on the other, the head being poised in the middle of the 

 figure of 8 so formed. The rest of the body lies' variably disposed in 

 sinuous extension. Prior to its hasty stroke the erected part is swayed 

 slightly forwards and backwards, whilst the body is inflated and 

 deflated with agitation, and the tail briskly vibrated with emotion. 

 Poised thus, intently watching the object of its alarm for a favorable 



* Many of the species in this genus are so closely alike in scale characters that it is diffi- 

 cult to separate them , consequently some have been much confused by some authors. 

 After the number of scale rows, the development of the vertebrals, and the number of the 

 subcaudals, the next most important point to demand attention appears to be the posterior 

 sublinguals the fellows of which are in contact in some of the species, separated completely 

 by small scales in others. Whether this will be found quite constant in the various species 

 remains open to question. The reflection of the pragocular on to the top of the head or 

 otherwise, appears to me of uncertain value, being subject to variation in individuals of some 

 species. The actual contact of this shield with the frontal is also variable. 



