( XXX ) 



Scales keeled in 19 rows. 8 upper labials, 2 entering the orbit. 



One prseocular. Three postoculars . . . T. Himalayanus. 



Two prseoculars. Three postoculars ... T. Ceylonensis. 



Scales keeled in 25 rows. 7 upper labials, 2 entering the orbit. 



Two prseoculars. Three postoculars ... T. plumbicolor. 



(Note. — The number of scales is that in the centre of the body, 

 on the neck there are two more rows.) 



Atretium. 



Scales keeled. One prsefrontal. 

 Back blackish olive ... A. schistosum. 



Xenocrophis. 



Scales keeled. One nasal. 

 Belly purple ; dark mottled ... X. cerasogaster. 



Family HOMALOPSID^. 



Freshwater or estuarine snakes. Nasals large. Nostrils 

 small, valvular. Eye small. Ventrals narrow. Caudals bifid. 



a. — Scales smooth. 



Gerarda. 

 Scales in 17 rows. One prefrontal. 

 Muddy olive with white lateral line ... G. bicolor. 



Cantoria. 

 Scales in 19 rows. A ring of orbital plates. 

 Dull yellow with numerous dark bands . . . C. Dayana. 



FORDONTA. 



Scales in 2.5 to 29 rows. One prefrontal. 

 Eye over the fifth labial ... F. bicolor. 



Eye over the third labial . . . F. unicolor. 



HYrSIRHINA. 



Scales in 19 to 23 rows. One prsefrontal. 

 Scales in 19 rows ... H. plumbea. 



Scales in 21 rows ... H. enhj'dris. 



