47 



B. Nostrils lateral. 



I. Teeth very small, equal, closely set, 37 50 in 

 each maxillary, head not or slightly distinct from 



neck; pupil round; scales smooth, in 17 rows. 9. Polyodontophis p. 54. 

 II. Maxillary with less than 40 teeth. 



| Head distinct from neck; internasals distinct 

 from praefrontals. 



1. Pupil round. 



a. Scales oblique, at least anteriorly. 



X Scales in 19 rows IO. Pseudoxcnodon p. 56. 



XX Scales in 13 15 rows. 



aa. Maxillary teeth 20 33 , posterior 



enlarged II. Dendrophis p. 57. 



bb. Maxillary teeth 1823, anterior 



longest 12. Dendrelaphis p. 67. 



b. Scales in longitudinal series. 



1. Scales in even numbers, 12, 16 or 18. 13. Zaocys p. 71. 



2. Scales in odd numbers. 



-(- Posterior maxillary teeth longest. 

 aa. Maxillary teeth 18 40, conti- 

 nuous; scales keeled, in 15 21 



rows 14. Tropidonotus p. 73- 



bb. Maxillary teeth 14 2 2, last two 



very large, separated from the 



others; scales keeled, in 19 rows. 15. Macropisthodon p. 91. 

 ir. Maxillary teeth 25 30; scales 



smooth, in 17 rows 16. Xenelaphis p. 93. 



dd. Maxillary teeth 12 20; scales 



smooth or keeled, in 13, 15 or 



17 rows 17. Zamenis p. 95. 



-\ |- Maxillary teeth equal. 



a. Ventrals rounded or angulate late- 

 rally; scales in 19 27 rows. . . 18. Coluber p. 98. 



b. Ventrals and subcaudals with a 

 lateral keel and a notch on each 



side; scales in 19 rows 19. Gonyophis p. 1 06. 



2. Pupil vertically elliptic. 



a. Anterior maxillary teeth enlarged, sepa- 

 rated from the rest. 



1 . Body long ; scales smooth or keeled, 



in 17 21 rows 20. Lycodon p. 107. 



2. Body extremely slender; scales keeled, 



in 17 rows 21. Lepturophis p. 113. 



