6 COLTTBBIDJB. 



Snout much depressed, strongly projecting ; nasal fused with the 

 internasal 101. Chilomeniscus. II. p. 272. 



** Anterior maxillary and mandibular teeth longest. 



102. Homalosoma, II. p. 273. 

 2. Scales without pits. 



a. Maxillary and mandibular teeth subequal, 15 to 35 ; 

 pupil round ; anterior temporal present. 



a. Loreal and prsefrontal not entering the eye. 



Head not or but slightly distinct from neck ; eye moderate or rather 

 small ; maxillary teeth 15 to 30. 



103. Ablabes, II. p. 277. 



Head distinct from neck ; eye moderate ; body stout ; maxillary 

 teeth 22 to 25 104. Grayia, II. p. 286. 



Head distinct from neck ; eye large ; maxillary teeth 35. 



105. XenuropMs, II. p. 288. 



/3. Loreal and preefrontal entering the eye, which,is small. 



Nostril lateral, between two nasals. 



106. Virginia, II. p. 288. 



Nostrils directed upwards, in a semidivided nasal ; two internasals. 



107. Abastor, II. p. 289. 



Nostril directed upwards, in a semidivided nasal ; a single inter- 

 nasal 108. Farancia, II. p. 290. 



6. Posterior maxillary and mandibular teeth shortest; 

 anterior temporal usually present. 



a. Head distinct from neck ; pupil vertically elliptic. 



Vertebral row of scales enlarged ; eye large. 



109. Petalognathus, II. p. 292. 



Dorsal scales equal ; eye moderate or large. 



110. Tropidodipsas, II. p. 294. 



Dorsal scales equal; eye small. 111. Dirosema, II. p. 298. 



/3. Head not distinct from neck ; pupil round or vertically 

 subelliptic 112. Atractns, II. p. 60Sr- 2 oC 



c. Maxillary teeth small, subequal, 8 to 12 : anterior 

 temporal present ; eye very small. 



Nostril in a single nasal ; loreal and pnefrontal entering the eye. 



114. Carphophis, II. p. 324. 



Nostril between two nasals and the internasal ; snout with angular 

 horizontal edge 116. Geagras, II. p. 326. 



