SNAKES OF CEYLON. 531 



Echis carinatus (Schneider). 



(Latin " carinatus " keeled, in allusion to its scales.) 

 The Saw-Scaled Viper. 



Tamil : " surattai pambu " (coiled snake), " pul surattai " 

 (grass coiled snake). 



Synonymy.— Pseudoboa carinata, Boa horatta, Scytale bizo- 

 natus, S. pyramidum, Viper a carinata, V. echis, Echis ziczac, 

 E. arenicola, E.frenata, E. superciliosa, Toxicoa arenicola. 



History. — Russell was the first to refer to the species in 1796 

 (Vol. I.), and he figured it very nicely on Plate II. of that work. 

 Schneider christened it in 1801. 



General Characters. — Head subovate. Snout very short, 

 without canthus, rounded anteriorly. Eye large, the iris 

 golden yellow, and the pupil vertical. Nostril small, placed 

 rather high, lying between the nasals. The commissure of the 

 mouth is viperine ; the upper lip presenting a downward 

 rounded contour, corresponding to the position occupied by 

 the fang when the mouth is shut. Neck markedly constricted . 

 Body cylindrical, short, and stout, attenuating towards the 

 neck, and also posteriorly towards the vent. It is very rough, 

 especially so in the flanks from the keeled and serrate condition 

 of its scales, dorsally lustreless, in striking contrast to the 

 highly polished ventral aspect. Belly rounded. Tail short, 

 about one-tenth to one-eleventh the total length. 



Identification. — The following characters will distinguish it 

 from other Ceylon snakes. The head is covered on the top 

 with small scales throughout, and the subcaudal shields are 

 entire. The serrated keels on the flanks are seen in no other 

 snake, so that it is very easily recognized. 



Colouration. — As in nearly all the vipers the colouration and 

 markings are very variable. Mr. Boulenger* speaking of 

 another viper (Vipera ursinii) says "I must observe that 

 vipers generally vary so much, both individually and according 

 to localities, that little reliance is to be placed for specific 

 distinction on that character." This remark certainly applies 

 to the saw-scaled viper. 



* Proc. Zool. Soc, Lond., 1893, p. 598 

 73 6(6)20 



