90 JOURNAL, BOMBAY X AT URAL HIST. SOCIETY, Vol. XXVI. 



(Plate XVII) which appeared in 1796, and again in the Second 

 Volume ( Plate XL ) issued in 1801. It was first christened by 

 Schneider in 1799. Its synonymy differed with almost every 

 writer until 1864 when Gunther fixed the proper designation under 

 which it now rests. 



Nomenclature, (a) Scientific. — The generic title is from Greek 

 " kerberos," the famous three-headed dog that guarded the entrance 

 to Hades in Grecian mythology. The name appears to have been 

 suggested by the forbidding aspect of the snake. The specific name 

 is also from Greek (" rhunchos " snout, and " ops " face) 

 probably in allusion to the peculiar under-hung condition of 

 the lower jaw. 



(ft) English. — The dog-faced water snake seems to me appropriate, 

 and is not only distinctive but accords with the scientific generic 

 name. 



(c) Vernacular. — None known to me. 



General Characters. — The head is pear-shaped as seen from above 

 expanding considerably towards the occiput. The snout is narrow, 

 and in profile shows an unusually prominent lower jaw little if at 

 all shorter than the upper. This feature to a large extent gives 

 the snake its forbidding expression. The nostrils are directed 

 almost as much upwards as laterally and are narrow slits convex 

 forwards. They approach the condition seen in the sea-snakes. 

 The eye is rather small, directed as much upwards as laterally, and 

 the eyebrow is remarkably prominent. The iris is minutely 

 speckled with gold and reveals a vertically elliptical pupil. The 

 neck is fairly evident. The body is stout, and rough from the 

 strong keels on the costal scales. It is dull dorsally, glossy on the 

 belly, including the last three costal rows. The tail is short, rather 

 compressed at the base, and rapidly tapers to an obtuse point. It 

 is about one-fifth the total length of the snake. 



Dimensions. — Most specimens range between two and three 

 feet, and anything over this is unusual. The longest of which 

 I am aware is that reported by Stoliczka from Burma which was 

 four feet, two inches. 



Colouration. — The back is bluish grey when the snake is sub- 

 merged, lightish grey when dry. It is crossed by numerous ill- 

 defined but conspicuous darker bars involving one to two scales 

 in the length of the snake, the intervals involving five to seven 

 scales. These bars grow less distinct posteriorly, and the fore- 

 most are broken up into spots in some specimens. The dorsal 

 colouration ceases abruptly about midcosta, and is replaced by buff 

 subcostally, and venerally. The belly is buff coarsely spotted or 

 dappled with deep greenish black. The head is coloured above 

 like the back, and the grey is sharply defined j\ist above the 

 supralabials. The upper lip and chin are buff. A conspicuous 



