4; 



B. Nostrils lateral. 



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

 each maxillary, head not or slightly distinct from 



neck 5 pupil round; scales smooth, in 17 rows. 9. Polyodontophis p. 54. 

 II. Maxillary with less than 40 teeth. 



I Head distinct from neck; internasals distinct 

 from praefrontals. 



1. Pupil round. 



a. Scales oblique, at least anteriorly. 



X Scales in 19 rows 10. Psendoxenodon p. 56. 



XX Scales in 13 — 15 rows. 



rt«. Mamillary teeth 20 — 33, posterior 



enlarged II. Dendrophis p. 57. 



(5i5. Maxillary teeth 18 — 23, anterior 



longest 12. Dcndrelaphis p. 67. 



/'. Scales in longitudinal series. 



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



2. Scales in odd numbers. 



-|- Posterior maxillary teeth longest. 

 <7a. Maxillary teeth 18 — 40, conti- 

 nuous; scales keeled, in 15 — 21 



rows 14. Tropidonotus p. 73, 



hb. Maxillary teeth 14 — 22, last two 

 very large, separated from the 



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

 fc. Maxillary teeth 25 — 30; scales 



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



</(/. 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. Cohiber p. 98. 

 l>. Ventrals and subcaudals with a 

 lateral keel and a notch on each 

 side; scales in 19 rows 19. Gonyophis p. 106. 



2. Pupil vertically elliptic. 



a. Anterior maxillary teeth enlarged, sepa- 

 rated from the rest. 

 l.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. 



