1870.] Indian and Malayan Amphibia and Reptilia. 11X 



throat and fore-part of the belly ; the bases of the ventrals are usually 

 conspicuously darker than their centres. The tail is above always 

 coral red, or reddish brown, below darker, being marbled and 

 spotted with dark brown. 



This species recalls the variability of coloration noticed in T. Wag- 

 leri, Schleg., (Giinth., loc. cit. p. 388), and I was at first much 

 inclined to refer it to that species, but as the Nicobar form always 

 has only 21 rows* of very slightly keeled and rather large scales, both 

 must be kept distinct. Whether any of the numerous species, which 

 Gray describes in his Catalogue of Viperine snakes, (p. 9-11) and 

 which G ii n t h e r considers as varieties of T . Wagleri, are identical 

 with the Nicobar form, it is impossible to decide from G r a y's 

 descriptions. I have never noticed in T. mutabilis that the squarish 

 dark bands or spots extend on to the sides, much less on the belly ; 

 they are strictly dorsal, and each separated from the next by a narrow 

 pale greenish band which is connected with with the lateral longi- 

 tudinal band of the same pale color. The unicolored variety strongly 

 resembles T. purpureus, Gray, (G ii n t h. 1. cit. p. 387), but the 

 more slender habit, prehensile tail, smoothish scales in 21 rows, 

 readily distinguish both. 



As compared with T. porphyraceous, the distinctions just noticed are 

 equally valid ; the number of ventrals is in the present species con- 

 spicuously smaller than in the former. With T. gramineus, the num- 

 ber of series of scales agrees, but their form and slight carination as 

 well as the shape of the head, and other characters do not admit a 

 specific identification. Steindachner (Reptiles of the Novara, 

 p. 86) mentions three rather much injured specimens of T. purpureus 

 from the Nicobars ; he does not record the number of rows of scales, 

 but as these specimens were previously referred byFitzinger 

 to T. viridis, D a u d. (gramineus, S h a w), I suspect that they be- 

 long to the unicoloured variety of the present species. 



I have examined one specimen from the Andamans, 19^ inches 

 long, of which the tail is 2f, ventrals 163, subcaudals 52, (3rd and 7th 

 entire); color uniform above, paler and conspicuously reddish at 

 the sides, with an indistinct darker longitudinal band in the middle ; 



* Cantor says that in his puniceus (= purpureus) he counted once as 

 many as 31 rows of scales. 



