3^ 

 Key to the Indo-Australian species. 



A. Ventrals broader than the surrounding shields. 



I. Diameter of the eye about half its distance from 



the nostril; scales in 19 or 21 rows I. C riifiis p. 36. 



II. Diameter of the eye one third to one fourth its 

 distance from the nostril. 

 a. Interocular width equal to the length of the 



snout; scales in 21 rows 2. C. lincatus p. 37. 



/'. Interocular width more than the length of 



the snout; scales in 23 rows S-' C. opisthorhodus p. 38. 



B. No enlarged ventrals. 



1. Nasals forming a suture behind the rostral; 



scales in 20 rows 4. C botilengeri p. 38. 



2. Nasals separated from one another; scales in 



22 rows ^' C. isolcpis p. 38. 



I. Cylindrophis rufus (Laur.). 



Angtds rufa^ Laurenli, Syn. Rept. 1768, p. 71. 



Cylindrophis rtiftis^ Boulenger, Cat. Sn. I 1893, p. 135 (s. syn.). 



Diameter of the eye about half its distance from the nostril; 

 the distance between the eyes more than the length of the 

 snout ; nasals forming a suture ; frontal at least as large as the 



Fig, 19. Cylindrophis rufus (Laur.) X Va- I-ower view of head. X ^h- 



supraocular, larger than the parietals, as long as its distance 

 from the rostral or longer; six upper labials, third and fourth 

 entering the eye. Scales in 19 or 21 rows; ventrals not twice 

 as large as the neighbouring scales, 185—245; anal divided; 

 subcaudals 5 — 10. 



