SNAKES OF CEYLON. 267 



Genus DIPSADOMORPHUS. 



(Greek " dipsas "* a kind of snake, and " morphe " form, 

 i.e., like another genus to which the name Dipsas . 

 has been applied.) 



General Characters (for Indian species). — The members of 

 the genus have very distinctive characters, whereby they 

 are easily recognized. They vary in length from about 3 to 

 over 7 feet. Head subovate and markedly depressed ; 

 widest about midway between the eye and the neck. Muzzle 

 short, with obtuse canthus, and obtusely rounded anteriorly. 

 Eye large, with a vertical pupil. Nostril round, contained 

 equally in the anterior and posterior nasals, and occupying 

 about the median two-fourths of the depth of the suture 

 between them. Neck markedly constricted, and this, taken 

 with the shape of the head, leads many to suppose these snakes 

 are vipers. Body markedly compressed, attenuating towards 

 the neck and the vent. Belly rounded or obtusely angulate 

 laterally. Tail cylindrical, varying from about one -fourth 

 to one -fifth the total length. 



* Dipsas was applied to a snake whose indentity is now uncertain, 

 but the name has been retained, and is now applied to a genus of South 

 American snakes. The dipsas of the Ancients was reputed to be 

 venomous, and, according to some, one of the effects of its bite was an 

 insatiable thirst (Greek " dipsa " thirst), though Lucan makes it appear 

 that it was the creature itself that was afflicted with thirst. Thus, in 

 his Pharsalia, written in the first century A.D., he alludes to it on the 

 occasion when Cato was leading his army across the desert. The 

 passage has been thus translated : — 



And now with fiercer heat the desert glows, 

 And midday gleanings aggravate their woes ; 

 When, lo ! a spring amid the sandy plain 

 Shows its clear mouth to cheer the fainting train, 

 But round the guarded bank in thick array 

 Dire aspics roll'd their congregated way, 

 And thirsting in the midst the dipsas lay. 



