2 COLUBRIDJ3. 



Maxillary teeth 6 to 9 ; scales without pits ; snout cuneiform, pro- 

 jecting T 55. Lytorhynchus, I. p. 414. 



Maxillary teeth 12 to 16 ; scales with apical pits. 



89. Hypsiglena, II. p. 208. 



2. Palatine and ptorygoid bones toothed ; pupil round ; an- 



terior mandibular teeth much larger than the posterior ; 

 scales with apical pits. 



a. Internasal shield entering the nostril; maxillary teeth 



12 to 14 52. Pseudaspis, I. p. 373. 



b. Internasal not entering the nostril. 



a. Lateral scales disposed obliquely, at least on the 

 anterior part of the body ; eyes large. 



Maxillary teeth 15 to 20, the posterior slightly enlarged ; scales in 

 21 to 25 rows 58. Phrynonax, II. p. 18. 



Maxillary teeth 20 to 32, the posterior strongly enlarged ; scales in 

 13 or 15 rows 71. LeptopMs, II. p. 105. 



/3. Scales forming longitudinal series ; maxillary teeth 11 

 to 20. 



Posterior maxillary teeth strongly enlarged and separated from the 

 rest by an interspace ; scales narrow, lanceolate. 



72. Uromacer, II. p. 115. 



Posterior maxillary teeth slightly enlarged. 



73. Hypsirhynclius, II. p. 117. 



Posterior maxillary teeth strongly enlarged and separated from the 

 rest by an interspace ; scales moderately elongate. 



74. Dromicus, II. p. 118. 



3. Palatine and pterygoid bones toothed ; pupil round ; man- 



dibular teeth subequal, or anterior a little enlarged. 



a. Longitudinal series of scales in even numbers ; maxillary 



teeth 20 to 33. 



Scales forming longitudinal series. 



53. Zaocys, I. p. 374. 



Lateral scales oblique 63. Herpetodryas, II. p. 71. 



b. Longitudinal series of scales in odd numbers; ventrals 



rounded or obtusely angulate laterally ; subcaudals not 

 angulate laterally. 



a. Maxillary teeth forming a continuous series, or the 

 last two or three separated from the rest by a very 

 short interspace. 



