SNAKES or CEYLON. 3 



TAIL ROUND IN SECTION. Families. 



(B) Ventrals enlarged, but not twice last costal 



row (see fig. 11 ). Anal divided into two ; 

 twice breadth of ventrals (see fig. 11 ). 

 Costala broader than long. 



(a) Supralabials f Our .. .. Uropeltidse 



(6) Supralabials six .. .. Ilysiidse 



(C ) Ventrals 2 to 2 J times breadth of last costal 



row (see fig. 17). Anal as broad as ven- 

 trals (see fig. 17). 



Costals broader than long. Bye mobile, 

 surrounded by many shields. 



Pupil vertical. 



(o) Costals in 15 rows at midbody . . *Xenopeltidse 

 (6) Costals more than 40 rows at mid- 

 body . . . . BoidsR 



(D ) Ventrals more than three times as broad as 



last costal row. Anal as broad as ven- 

 trals. Costals as long or longer than 

 broad. Bye mobile, surrounded by 

 many shields. 



(a) No mental groove. -Three pairs of 

 large asymmetrical sublinguals. 

 Pupil vertical . . . . * Amblycephalidas 



(6) A mental groove. Two pairs of sub- 

 linguals (see fig. 20). Pupil variable 

 (except Ohersydrus-\) . . Colubridse (ex- 



cept Hydro- 

 phunae) 

 (c) A mental groove. One pair of sub- 

 linguals (see fig. 91 ). Pupil variable Viperidfe 



TAIL COMPRESSED INTO A FIN . . Sub-family Hy- 



drophiinse of 

 Colubridse 

 For Ceylon Species. 

 Ventrals not enlarged . . Typhlopidse 



Ventrals enlarged : — 



Last costal row | breadth of ventrals. Anal 

 twice or nearly twice breadth of ventrals : — 



Eye in a single shield . . Uropeltidse 



Eye surrounded by shields . . Ilysiidse 



Last costal row J breadth of ventrals. Anal 



as broad as ventrals . . . . Boidse 



Last costal row one-third or less the breadth of 

 the ventrals. Anal asbroadasventrals:- — 



Two pairs of sublinguals . . Colubridse 



One pair of sublinguals . . Viperidse 



* Not represented in Ceyloii. 



t Chergydrtia has no ventral shields developed, its costals broader 

 than long, no mental groove, and no sublinguals. 



