JlERl'ETOLOGV. 319 



n. XIGROCISCTA, D;Ul(l. 



Head small. Scales keeled, 29 rows on tlio neck. The fourtli labial under tlio 

 orlnt. Ventralfl .'520 to a.'M, not twice as largo as the adjoining; scales, and smooth. 

 Trunk surrounded by 53 black rings, narrower than the interspaces, ;i and 5 scales 

 broad respectively. Colour greenish olive, yellowish on the sides. Tail with 9 to 1 1 

 black bars. 



(I. Hi-ad venj fniuiJl. Xcck veri/ uli'inler. 



'" One poxfacular. Th» third upper lahliil mt in. cunttiot with the nasal. 



H. cni-oKis, Daud. 



Scales tubercular and faintly keeled, 31 rows on the neck. Ventrals 473 to 500, 

 not much larger than the adjoining scales. Greenisli-olivo above, yellowish on tho 

 sides. From 59 to 67 rhombic bands on the back, which are narrower and fainter on 

 the sides, but extend round tho belly, where the yellowish ground colour sometimes is 

 reduced to a pair of spots. 



II. LixnsAYi, (fray. 



Hardly separable from tlic last, but is said (o have a shorter neck and fewer 

 bands. 



H. i,\TiFAscLiTA, Giintlicr. 



Head small. Scales keeled, 23 rows round the neck. The third labial not in 

 contact with the nasal. Ventrals 322, distinct. The anterior twice as broad as the 

 scales, the posterior bicariuate. Terminal scale of tail very large. Trunk with 

 38 broad black cross-bands, confluent above and below, and darker below. The 

 yellow colour only shows as large rounded lateral spots. 



Mergui. 



H. coEOXATA, (iiiuther. 



Head very small. Scales keeled on the back, tubercular on the sides. Yentrals 

 321 to 337, bitubercular, nearly twice as large as the adjoining scales. Trunk with 

 53 to 59 complete black rings, broader than the interspaces, which are yellowish- 

 olive. Head and under the neck black. A yellow horse-shoe on the head. Tail 

 \N ith 1 1 blackish bars. 



** Two 2>oducidars. The third upper lahial not in contact with the nasal. 



H. ATEICEPS, Giinther. 



Head small. Scales, with a small apical tubercle, 26 to 28 rows on the neck. 

 Yentrals 376, anteriorly twice as large as the adjoining scales, posteriorly smaller, 

 bitubercular. Back witli ()2 blaokish-olivo cross-bands, tangential on the vertebral 

 line. Sides yellowish white. Head black. 



H. DiADEMA, Giinther. 



Head very small. Scales tubercular, 33 rows on the neck. Ventrals 318, only 

 on the neck twice as large as the adjoining scales. Trunk with 63 blackish rings 

 broader than the interspace, and narrower and paler on the belly. Head blackish, 

 with two yellow converging superciliary bands. Tail 7 to 9 blackish cross-bars. 



B. Scales not imbricate, placed side hij side. 



a. Head very small, and nech very slender. 



* One postocular. 



H. oitACiLis, Shaw. 



The third upper labial not in contact with the nasal. Scales tubercular, 21 rows 

 on the neck. Ventrals 230 to 290, anteriorly twice as largt' as the adjoining scales, 

 posteriorly smaller, and divided. Trunk anteriorly surrounded by blackish rings. 

 Behind gi-eenish-olive, whitish below. Throat and crown of head blackish. 



