62 REPTILES. 



before the anus, and measuring 21" in length, form twenty-three 

 complete spirals, ending in a rectum two inches long. — This 

 highly interesting snake, I think, is the first freshwater Coluber 

 known from Africa. Allied to some HomalopsidcB, it differs by 

 its form, by its scales, and by its dentition, which characters appear 

 to be sufficient for establishing a new genus. I name it in honour 

 of Dr. J. E. Gray, who, after gathering this rich collection during 

 many years, has charged me with the task, as pleasant as it is 

 difficult, of giving a systematic account of it. 



2. ToMODON, Dum. Sf Bibr. 



Posterior maxillary tooth very long and grooved ; anterior teeth 

 short, of equal length. Scales smooth, narrow, very imbricate, 

 in seventeen or nineteen rows; anal bifid. One anterior, two 

 posterior oculars ; anterior frontals pointed in front ; one nasal, in 

 the middle of which is the small nostril ; rostral hardly reaching 

 the surface of the forehead ; vertical rather elongate. Head fiat, 

 triangular, distinct from neck. South America; India. 



Tomodon, sp., Dum. ^ Bibr. vii. p. 932. 



1. Tomodon strigatus. 



Brown : on each side from the nostril to the tip of tail a narrow 

 black stripe ; on each side of belly a second one from the chin to 

 the tip of tail. 



a. Adult. India. From Mr. Warwick's Collection. 



Description. — Body very stout and thick, with slender neck and 

 flat belly, rather compressed towards the tail ; tail thin, distinct 

 from body, tapering, moderate. Head conical, high, broad be- 

 hind, distinct from neck, with flat crown and rounded pointed 

 muzzle ; eye moderate, pupil ? Rostral shield small, not much 

 convex, five-sided, rounded above, just reaching the surface of 

 forehead ; anterior frontals small, rectangular, triangular, pointed 

 in front; posterior frontals small, convex, bent on the sides; 

 vertical elongate, more than twice as long as broad, with nearly 

 parallel outer edges and a right angle behind. Occipitals mode- 

 rate, hardly forked behind ; superciliaries elongate, prominent 

 above the eye ; anterior ocular just reaching the surface of head, 

 two posterior ones ; loreal quadrangular (on one side united with 

 frontal) ; one large nasal, pierced by the nostril ; eight upper 

 labials, fourth and fifth forming the lower edge of eye ; two larger 

 temporal shields in contact with oculars, some smaller ones 

 behind. Scales smooth, in nineteen rows, very imbricate in not 

 very oblique rows ; those of the back rather short, with rounded 



