1870.] Indian and Malayan Amphibia and Reptilia. 215 



to the south of Ceylon is uniformly black above, yellow at the sides 

 and below, with remarkably elongated long blackish brown spots at 

 the sides ; tail reticulated with yellow and black ; the scales are 

 almost smooth. 



The species was taken also near the Andamans and the Nicobars ; 

 it seems to be common all through the eastern seas. 



Fam. Crotalidjs. 



Trimeresurus, L a c e p. 



The difficulty in discriminating various species of this genus is 

 well known. There is hardly a single character which could be 

 confidently relied upon as constant, but the average number of 

 rows of the scales and their form, as well as the shape of the head 

 appear to be more useful in the determination of species than any 

 other character, this of course applying to specimens of about 

 equal size. The number of small shields behind the rostral is very 

 variable, and the second upper labial is sometimes divided in two 

 parts on one side, while it remains single on the other in one and the 

 same specimen ! The size of the supraciliaries is, however, tolerably 

 constant. 



The effect of the bite of a Trimeresurus does not as a rule appear 

 to be nearly so fatal, as is for instance that of Daboia Russettii. This 

 is often due to the difficulty accompanying the ready use of the long 

 and rather strongly bent fangs, but mainly, I think, to the smaller 

 size of the poison gland. The last is situated in Trimeresurus along 

 the lower posterior edge of the maxillary, covered above by the 

 masseter and post-temporal muscles, and laterally only by the skin ; 

 its form is simple, not provided with any appendages, as in the 

 Cobra. The small size of this gland in some species, as for instance 

 in T. Cantoris from the Nicobars, is very remarkable, for in some 

 specimens between 3 and 4 feet in length it is not much longer than 

 half an inch, and about a quarter of an inch high, with a canal in 

 front, of about half an inch, leading to the fang. Dr. E i n k says that, 

 during his stay at the Nicobars, he was informed of the existence of 

 great many vipers in the jungles, but he never heard of a fatal case 

 resulting from their bite. Occasionally, he says, a native was seen 

 with a swollen foot, but it always soon passed away. I made in- 



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