1920.] Dr. Maixolm Smith : Sea Snakes. 27 



accredited count for gracilis being 29 to 33. Since then I 

 have obtained a specimen having 33, and Wall has also 

 published an account of a large series of gracilis obtained 

 on the Indian coast (Journ. Bombay, Nat. Hist. Soc. 1. c. s.). 

 His maximum is only 33, but his count is made at. mid-body, 

 and I find on counting my own specimens at that point, an 

 allowance of from 2 to 4 scales may be made for the 

 difference in position. 



This brings them much nearer to my own specimens, 

 and as there appears to be no other character by which they 

 can be separated, I unite them. Wall's series is a fine one 

 of 36 examples, and should be fairly representative of the 

 locality (Madras). After allowing for all discrepancies in 

 our method of counting, however, there still remains a con- 

 siderable difference between his series and mine with regard 

 to the number of scales round the neck and body. I tenta- 

 tively define the two forms as follows : — 



Madras Coast. 



17 — 19 round the neck ; 29 — 37 round the body. Ven- 

 trals, 215—297. Av. 251. 



Malay Peninsula and Gulf of Siam. 



19 — 23 round the neck ; 33 — 41 round the body. Ven- 

 trals, 250— 302. Av. 279. 



Two races appear to be clearly indicated, but with the 

 type locaUty of this snake unknown, it would be as well to 

 know something about the forms found elsewhere before 

 proceeding to name them. 



Variation. — The variation in my specimens is as 

 follows : — Eye equal to or slightly less than its distance from 

 tlie mouth ; rostral as broad as high or a Uttle broader than 

 high, the portion visible above equal to three-quarters or the 

 entire length of the internasal suture ; frontal usually 

 shorter than its distance to the rostral ; five or six suprala- 

 bials, in one example only the fourth shield touching the 

 eye. Fragmentation of the supralabials does not occur in 

 any example, nor are there any small scales interposed 

 between the infralabials. 



Colour, (in alcohol). Pale bluish-grey on the upper 

 half of the body, yellowish or whitish on the lower, the 

 young with indistinct darkish dorsal bars or complete bands. 

 Head grey, yellowing with age. 



No. 1105 has 55 bands upon the body, about as broad 

 as their interspaces on the sides of the body, slightly dilated 

 dorsally and ventrally ; on the posterior part of the body 

 they are very indistinct. Tail grey, blackish at the tip. 



Dentition. — Posterior maxillary, 5 ; palatine, 8 ; ptery- 

 goid, 10 — 12 ; mandibular, 13 (3 specimens examined). 



The type of my original H. rostralis is No. 1102, in the 

 Selangor Museum, Kuala Lumpor. 



Hydrophis viperina (Schmidt). 



Distira viperina, Bouleng., Cat. Sn. B. M., Ill, p. 298 (1896) ; 

 Wall, Mem. Asiat. Soc. Bengal, II (8), p. 239 (1909). 



