1120.] Dr. Malcolm Smith : S^fl Sna/res. 33 



Females. 



Round the neck :— 27 to 35 (usually 29 to 33) . Round 

 the body :— 33 to 41 (usually 35 to 37) . Ventrals :— 141 to 

 230.^ 



That marked sexual variation existed in this species 

 was observed long ago by Boettger in working on Philippine 

 specimens, (Zool. Anz./p. 395, 1888), but his observations 

 seem to have been overlooked by most authors in writing 

 since. 



Boettger's remarks apply chiefly to the ventral shields, 

 and the figures he gives (I quote 3tejneger, p. 401) are 135 — 

 168 for males, 186 — 237 for females. I cannot but think 

 that had he worked on a larger series — he had only 31 

 specimens — the difference which he found between the 

 sexes would have been less marked. Apart from this, his 

 figures, both in range and average, are considerably higher 

 than what is recorded by any other author for this species. 

 It looks indeed as if the Phillipine form differed from the 

 others, although it is possibly due to the different method 

 employed in counting these scales.^ 



Colour. — Greenish or yellowish olive above, whitish 

 below, with from 35 to 50 dark grey or olive dorsal bars, 

 tapering to a point on the sides. Variations to this are 

 frequent. The dorsal bars may be continued round tlie 

 body as complete bands, a form seen most frequently in 

 juveniles. A narrow black ventral stripe is sometimes 

 present, or less frequently, a broad irregular ventral band. 

 Coalescence of the dorsal bars occurs in adults, and in 

 some the entire back is of one uniform colour. One speci- 

 men (No. 2460) is uniform slate grey throughout. Young 

 ones have the head black, with or without yellow markings 

 across the snout and along the sides of the head. 



Specimens from Koh Kong are, as a series, greyer and 

 darker than those from the head of the Gulf, and are more 

 prone to have ventral stripes and bars. 



Ouwen's coloured figure is an excellent representation 

 of many examples found at the head of the Gulf. 



Variation. — Fission of the second supralabial to form 

 a pseudo-loreal is not uncommon. 41 scales round the body 

 occurs in 2 examples only, and in one of these (No. 3883), 

 the ventral count is 230, the next number in sequence to it 

 being 203 (No. 1391). 



' Ventral counts are very tedious, and the figures given here 

 are drawn mainly from specimens obtained in the Gulf of Siam. 



"The ventral shields of Enhijdris are very irregular in their 

 disposition, sometimes being broken up, with odd scales interposed 

 here and there, sometimes missing altogether. The method I have 

 used has been to control the count by means of the adjacent row 

 of body scales, which, being uniform in their sequence, indicate 

 what the correct ventral count should be. • 



