SNAKES OF CEYLON. 27 



Genus SILYBURA. 



(Greek "silubon " thistle, " oura " tail, in allusion to the 

 spines at the tail tip.) 



General Characters. — Small snakes ranging between 1 and 

 2 feet. Head small ; snout pointed, obtusely pointed, or 

 bluntly rounded. Eye in the ocular shield. Nostrils small, 

 round, pierced in the anterior -inferior quadrant of the nasal 

 shield. Chin with no mental groove. Neck stout. Body 

 short to moderate, stout, cylindrical. Belly rounded. Tail 

 cylindrical or compressed basally, convex above, or with a 

 flattened disc. 



Identification. — The terminal caudal shield is of a character 

 peculiar to the genus. (See fig. 10.) 



Habits. — Subterrestrial. Sluggish. Very gentle. 

 Food. — Seem to subsist entirely on worms. 

 Breeding. — The method of reproduction is in many Indian 

 species viviparous. 



Poison. — Not poisonous. 



Lepidosis. — Rostral : Touches four or six shields. Nasals : 

 Meeting or nearly meeting behind the rostral. Internasals : 

 None. Prefrontals : Present. Frontal : Present. Supra- 

 oculars : None. Parietals : Present ; as long as, or slightly 

 longer than the frontal. Loreal : None. Ocular : A large 

 shield containing the eye. Temporal : None. Supralabials : 

 Four ; 1st and 2nd touching the nasal, 2nd and 3rd the 

 prefrontal, and 3rd and 4th the ocular. Sublinguals : 

 None. 



Costals : Broader than long ; broadly rounded posteriorly ; 

 rectiform ; smooth ; vertebrals not enlarged ; last three or four 

 rows enlarged ; ultimate row two-thirds to three-fourths the 

 breadth of the ventrals. Ventrals : Enlarged but narrow. 

 Anal : Divided ; twice the breadth of the ventrals. Supra- 

 caudals : Strongly keeled ; forming an oval disc in many of the 



