( xxix ) 



HeRPET> 'REAS. 



Last lengthened maxillary in a continuous line with the rest. 

 Ventrals strongly bent at the side ... H. Sieboldii. 



Group d. — Natricina. 

 Freshwater Colubrines. 



Tropidonotus. 

 Scales keeled. Two prsefrontals, 



Scales smooth in 15 rows, 



1 prseocular. 3 postoculars ... T. punctulatus. 



1 pr^eocular. 3 postoculars. Nape black 



banded ... T. zebrinus. 



Scales smooth in females, faintly keeled in males in 19 rows. 

 TJpperlabials 8. 1 prseocular. 2 postoculars T. platyceps. 



Scales keeled in 17 rows. Upper labials 8. 



1 praeocular. 3 postoculars ... T. macrops. 



2, 3 or 4 praeoculars. 4 or 5 postoculars ... T. angusticeps. 

 Penultimate and preceding upper labial 



large ... T. nigrocinctus. 



Scales keeled in 19 rows. 9 upper labials, 3 entering the orbit. 



" Well developed valvules in the nostrils " T. quincunciatus. 

 Occipitals larger than vertical ... T. junceus. 



Occipitals nearly equal, vertical and post- 



frontals ... T. Beddomei. 



Prsefrontals smaller though longer than 



postfrontals . . . T. bellulus. 



Scales keeled in 19 rows. 8 upper labials, 3 entering the orbit. 



Praefrontals sub-truncate in front . . . T. subminiatus, 



Prsefrontals pointed in front ... T. stolatus. 



Prsefrontals truncated in front. Green with 



black cross bars . . . T. monticola. 



-:.St 



