1. GERRHONOTTJS. 267 



Sy^iojysis of the Species. 

 I. Dorsal scales larger than ventrals. 



A. An azj-gos praefrontal shield. 



1. Nuchal scales in four longitudinal series. 



No granular zone in the lateral fold ; no 



fold along the side of the neck 1. oaxacce, p. 268. 



Lateral fold enclosing granules ; a slight 



fold along the side of the neck 2. gramineiis, p. 269. 



2. Xuchal scales in six or more longitudinal series. 



a. No projecting scales above the ear. 



Azygos praefontal completely enclosed be- 

 tween two pairs of prsefrontals ; 13 or 

 14 longitudinal series of ventrals .... 3. dejjjpii, p. 269. 



Azygos praifrontal separated from the 

 loreal by a small canthal shield ; ven- 

 trals in 12 longitudinal series 4. tceniatus, p. 270. 



h. A series of projecting scales above the ear. 



Dorsal scales in 12 or 13 longitudinal 



series 5. vasconcelosii, p. 270. 



B. No azygos prsefrontal. 



1. A series of projecting scales above the ear. 



Four pairs of shields between the frontal 



and the rostral 6. Jimbriatus, p. 271. 



Three pairs of shields between the frontal 



and the rostral 7. auritus, p. 271. 



2. No projecting scales above the ear. 



35 to 40 transverse series of dorsal scales 



between the head and the base of the 



tail, and 12 or 14 longitudinal series . . 8. imbricatus, p. 272. 



27 transverse series of scales 9. rudicollis, p. 272. 



16 longitudinal series of dorsal scales. . . . 10. planifrons, p. 273. 



II. Dorsal scales not or but scarcely larger than ventrals. 



A. Lateral dorsal scales keeled. 



Dorsal scales in 14 or 16 longitudinal 



series 11. ccsruleus, p. 273. 



B. Lateral dorsal scales smooth. 



1, An azygos pra^frontal, separated from the frontal by a pair 

 of prsefrontals. 



