1. VARANXrs. 305 



B. Abdoiniiial scales keeled. 



1. Nostril equallj' distant from the 



orbit and the end of the snout . . 8. grayi, p. 312. 



2. jS'ostril much nearer the orbit than the end of the snout. 



Snout moderate ; dorsal scales large ; nu- 



chals not keeled 9. damerilii, p. 312. 



Snout very long, pointed ; nuchal scales 



extremely large and strongly keeled . . 10. rucUcollis, p. 313. 



3. Nostril much nearer the end of the 



snout than the orbit 11. salvadorii, p, 314. 



III. Nostril round or oval ; tail compressed, keeled above. 



A. A transversely dilated median series of supraocular scales. 



1 . Nostril oval, at least twice as far from the orbit as from the 



end of the snout. 



a. More than 80 transverse rows of abdominal scales from 

 gular fold to groin. 



a. Nuchal scales not larger than 



dorsals 12. saJvator, p. 314. 



/3, Nuchal scales larger than dorsals. 

 Nuchal scales larger than occipitals .... 13. nuchalis, p. 315, 

 Nuchal scales smaller than occipitals .... 14. cumingii, p. 316. 



h. Less than 80 rows of scales 



from gular fold to groin .... 15. togianus, p. 316. 



2. Nostril round. 



Nostril considerably nearer the end of the 



snout than the orbit; nuchal scales 



very small, keeled, separated by very 



wide interspaces 16. kalabecJc, p. 316. 



Nostril a little nearer the end of the snout 



than the orbit 17. indicus, p. 316. 



B. Supraocular scales subequal. 



1. Nostril a little nearer the orbit 



than the end of the snout .... 18. niloticiis, p. 317. 



2. Nostril nearer the end of the snout than the orbit. 



Nostril twice as far from the orbit as from 



the end of the snout ; scales on upper 



surface of head larger than temporals. . 19. varias, p. 319. 

 Nostril more than twice as far from the 



orbit as from the end of the snout ; 



head-scales very small 20. fjiyantens, p. 320. 



Nostril a little nearer the end of the snout 



than the orbit ; head-scales very small. 21. (jonhlii, p. 320. 



VOL. II. X 



