COLTTBEISa. 5 



6. Posterior maxillary teeth separated from the rest by an 

 interspace. 



I -with apical pits 95. Leptocalamus, II. p. 249. >" 



Scales without pits 96. Arrhyton, II. p. 251. 



D. Maxillary teeth equal or nearly so, or posterior decreasing in 

 size. 



1. Scales with apical pits. " 



a. Longitudinal series of scales in e-ven numbers ; eye large ; 

 no subooulars .... 59. Spilotes, II. p. 23. 



6. Longitudinal series of scales in odd numbers. 



a. Head distinct from neck ; eye moderate or large ; body 

 usually much elongate. 



* Maxillary teeth nearly equal ; scales forming straight 



longitudinal series. 



Nasals distinct, not fused with the loreal ; ventrals rounded or more 

 or less distinctly angulate laterally. 



60. Coluber, II. p. 24. A 



Nasal single, fused with the loreal, in contact with the prseocular ; 

 ventrals sharply angulate laterally. 



61. Synchalinus, II. p. 70. X 



Nasals distinct ; ventrals and subcaudals with a suture-like lateral 

 keel and a notch on each side corresponding to the keel. 



62. GonyopMs, II. p. 70. 



** Posterior maxillary teeth decreasing in size ; scales 

 narrow and oblique; ventrals and subcaudals with 

 a suture-like lateral keel and a notch on each side 

 corresponding to the keel. 



65. Dendrelaphis, II. p. 87. 



/3. Head not or but slightly distinct from neck. 



* Maxillary teeth equal or subequal. 



Snout cuneiform ; rostral shield with obtuse horizontal keel. 



97. Simophis, II. p. 253. ' 



Snout beak-shaped, hooked; rostral shield with sharp horizontal 

 keel 98. ScaphiopMs, II. p. 254. 



Snout obtuse or pointed ; nasal distinct from the labials. 



99. Contia, II. p. 255. ' 



Snout pointed; rostral in contact with'dr approaching the frontal; 

 nas^ fused with the first labial. 



100. Picimia, II. p. 270, 



