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Adult ?-Crown shields light chestnut ; lips and throat pale yellow; ground colour above pale greenish yellow, sides and abdomen buff with numerous distant black transversal bands, becoming indistinct towards the tail and on the sides, where the scales are partially edged or spotted with black. The interstitial skin of the back and sides black, of the abdomen buff. Iris dark grey with a buff orbital margin ; pupil black minute ; tongue buff.

Central abdominal series of larger scales, 347 +41. Habit.-Sea of Pinang and Malayan Peninsula.

Sea of Liewkiew Islands, Timor, Sumatra, Bay of Bengal. The eyes are lateral, sunk, excessively small, of a diameter equalling the large almost vertically opening nostrils. The single præ-orbital shield is beneath wedged in between the second and third upper labial. The latter, as well as the fourth and fifth, border the orbit beneath. Of the two post-orbitals the lower is wedged in between the fifth upper labial and the large shield resting upon the sixth upper labial. Abore the latter and the seventh, the cheeks are covered by three very large shields. The seven upper labials are large and very high. Of the nine inferior labials the two anterior are the largest, and placed vertically, the succeeding seven are smaller and placed nearly horizontally, so as to become partially hid when the jaws are closed. The chin is covered by the first pair of labials and two pairs of elongated mentals, between which and the inferior labials intervene on each side the second labial, three very large shields, and three smaller. The neck is covered by 37, the anterior part of the trunk by 33, and the thickest by 40 longitudinal series of rhombic scales. In the individuals examined by M. Schlegel, all of less length than my own, the series varied from 31, 29 to 27. The scales are rhombic with rounded apex, each scale with a small central tubercle, or an elevated (keeled) line, which however with age becomes indistinct or obliterated. The central larger

the period when the integuments are to be changed. Russell's description was copied by Daudin, who merely supplied the denomination of Hydrophis cyanocinctus, (Hydrus brugmansii, Boie, 1827,) upon which Wagler founded his genus Enhydris, 1830. According to M, Schlegel, all these are Synonyines of Hydrus nigrocinctus (Daudin). The only means of deciding the Synonymy of this and most of the other species appears to be a close examination of such original specimens, described by Russell and Shaw, which may at present exist in the collection of the British Museum.

abdominal scales are hexagonal, with or without a small tubercle on each side. The anus is covered by three or four excessively large scales. The larger individual of two was of the following dimensions : Length of the head,

O ft. 1 inch.
Ditto ditto trunk,

5
Ditto ditto tail,

0 49

6 ft. 0.9 inch. Circumference of the neck, 33, greatest do. of the trunk, 43 inch.

HYDRUS NIGROCINCTUS, (Daudin.)
Syn.*-Russell, II. Pl. 6. Kerril Pattee, 1801.

Hydrophis nigrocinctus, Daudin, 1803.
Hydrophis melanurus, Wagler, 1828.
Polyodontes annulatus, Lesson, 1833.
Hydrophis nigrocincta, Schlegel, 1837.

Hydrophis nigrocincta, Schlegel, apud Cantor, l. c. New born.-Ground colour buff or bluish-white; upper-lips and muzzle black, and a transversal band across the hind head, from whence proceeds a triangular or cross mark towards the vertex ; gular and inferior labial shields edged and spotted with black; trunk and tail with numerous black transversal bands, either encircling the body, or interrupted on the abdominal ridge, where appear a few indistinct black spots; apex of the tail black. Entire length 84 inch.

Older.-Greyish green olive above, yellowish on the sides, buff be. neath; the bands less intense black, often placed obliquely so as to join each other on the back. Iris grey ; pupil circular, black; tongue buff. Central abdominal series of larger scales, 281+ 41; 284+ 43; 289+ 39. Habit.-Sea of Malayan Peninsula, Pinang, Singapore.

Estuaries of the Ganges, Bay of Bengal. This species greatly resembles H. striatus, from which it differs in the more compressed general form ; the eye though small, is of a larger diameter than the nostril, and it is surrounded by a single post-orbital shield, which beneath is wedged in between the fourth and fifth upper labial, and the præ-orbital between the second and third. The orbit is bordered beneath almost entirely by the fourth upper labial. The

Doubtful SYN.-Russell, II. Pl. 13, Kuddell Nagam, 1801. (Enhydris gracilis, Merrem, 1820.) Hydrus spiralis, Shaw, 1802.

sixth

upper labial is the largest, in some individuals covering the cheek and bordering above the occipital. Of the seven or eight inferior labials the four anterior are very large ; above the third there is one or two small triangular shields; the other three or four posterior labials are very small elongated. There is no horizontal series of labials as in H. striatus, and the two elongated pairs of mentals immediately border the labials. The neck is covered by 33, the thickest part of the trunk by 53 longitudinal series of scales. Those examined by M. Schlegel, the length of which exceeds those come under my own observation, had 27, 29 to 31 series of scales. Those of the anterior part of the back are rhomboidal, those of the posterior part rhombic with rounded apex and slightly imbricate ; those of the sides hexagonal: all have either a sharply raised keel or a central tubercle, both of which fre. quently become obliterated. The central series of abdominal scales are a little larger than the rest, frequently divided in two hexagonal, and with a small tubercle on each side, which often becomes indistinct, or obliterated. The anus is covered by 3 or 4 very large, or by a series of small scales. The largest of six individuals was of the following dimensions : Length of the head,

O ft., 05 inch.
Ditto ditto trunk,

2 03
Ditto ditto tail,

0 26

2 ft. 39 inch, Circumference of the neck, g; greatest do. of the trunk, 2 inch.

Var.? (See Pl. XL. Fig. 8.) Crown shields olive green with a blackish band from the eyes over the anterior part of the upper lip; the posterior part and the lower lip pale yellow ; ground colour of the trunk greenish lead grey above, pale yellow on the sides, beneath buff, with numerous black transveral bands. Iris amber-coloured with the orbital margin dark grey. Central abdominal series of scales 235 +38.

It differs from the preceding in the following particulars. The head is proportionally shorter, broader triangular, the muzzle more pointed, and the upper surface from the vertical shield very declivous. The eyes are much larger than the nostrils, with a single præ-and postorbital, but bordered beneath by the third and fourth upper labial,

The latter, six in number, present nothing abnormal. The lower
labials are also six, proportionally larger than in the preceding. The
mouth is smaller. The make of the trunk is more robust; the neck is
covered by 15, the thickest part of the body by 21 longitudinal series
of proportionally much broader hexagonal scales, tuberculated on the
anterior part of the trunk, on the rest keeled, forming series of sharp,
continued ridges. The central abdominal series is at first somewhat
larger than the rest, angular, with a small more or less distinct tubercle
on each side. A single individual, captured in a fishing stake off
Pinang, was of the following dimensions :
Length of the head,

O ft. Og inch.
Ditto ditto trunk,

1 64
Ditto ditto tail,

0 24

1 ft. 99 inch. Circumference of the neck, 1%, greatest do. of the trunk, 2; inch.

HYDRUS GRACILIS, Shaw.
Syn.*-Russell, I, Pl. 44, Tatta Pam, 1796, (very young.)

Hydrus fasciatus, apud Shaw (Russell, I, 44, excluding the other Syn.)

1802.
Angvis mamillaris, Daudin, 1803.
Hydrus, apud Wagler, 1830.
Russell, II, Pl. 7, Shootur Sun, 1801.
Hydrus cloris, Daudin, 1803.
Hydrophis, apud Wagler, 1830.
Russell, II, Pl. 8, Kalla Shootur Sun, 1801.
Hydrophis obscurus, Daudin, 1803.
Hydrophis, apud Wagler, 1830.
Hydrus fasciatus, apud Guérin : Iconog. Rept. Pl. 25, 1, 1829.
Pelamis chloris, Merrem apud Horsfield : Life of Raffles, 1830,
Microcephalus gracilis, Lesson, 1833.
Hydrophis gracilis, Schlegel (Syn. Angvis xiphura, Hermann, Typh-

lops, Merr. Tent. p. 158,) 1837.

Hydrophis gracilis, Schlegel, apud Cantor, I. c. Pl. 56, (Young.) New born.-Head shining intense black ; ground colour of the trunk and tail bright gamboge, on the back and sides interrupted by numerous black rings, which above are widened into lozenge shape, narrowed on the sides. Throat and anterior half of abdomen intense black, continued as a more or less distinct line to the black apex of the tail. On the sides the yellow ground colour appears in the shape of oval spots,

* DOUBTFUL Syn.-Angvis laticauda, Linné, Mus. A. F. 1754. Vosmaer, Monogr. Fig. 2, 1774, Hydrus fasciatus, Schneider, 1801.

gradually increasing in depth towards the tail. Entire length, 1 ft. 3 inch.

Adult ?-Head and back uniformly dark olive or brown, becoming greyish on the posterior half, and very indistinct or obliterated on the sides. In some a pale yellow spot on each side of the hindhead, and a third on the frontal shields. The lateral oval spots pale sulphur coloured on the anterior half, pale greenish yellow on the posterior. The black of the lower surface very pale, but distinct. Iris black ;

tongue buff.

Central abdominal series of larger scales, 454+60. HABIT.-Sea of Malayan Peninsula and Islands.

Bay of Bengal, Malabar, Sumatra, Borneo. In form and number the shields of the head resemble those of Aydrus nigrocinctus, so as to afford no distinguishing character. Yet it may be readily distinguished from that and other species by the excessive slenderness of the anterior, cylindrical part of the trunk, which from thence becomes much compressed, gradually increasing in bulk and vertical diameter till towards the tail, where the diameter again decreases. The scales of the cylindrical, anterior part of the trunk are rhomboidal with rounded points and slightly imbricate; the rest are hexagonal. The central abdominal series continued beneath the tail, consists of hexagonal scales, a little larger than the rest, and frequently longitudinally divided. In the very young all the scales are smooth,

the central abdominal ones acquire a small tubercle on each side, and those of the compressed sides and of the back each a central tubercle. In the largest individuals the central abdominal scales have three longitudinally placed minute tubercles on each side, and the rest of the hexagonal scales three or four similar central tubercles. In the new-born the neck is covered by 32, the bulkiest part of the body by 49 longitudinal series; these parts are covered by 26 and 44 series in the largest individual, which is of the following dimensions : Length of the head,

O ft. 05 inch.
Ditto ditto trunk,

3

25 Ditto ditto tail,

0 4

with age

3 ft. 7 inch. Circumference of the neck, 1%, of greatest do. of the trunk, 3. inch.

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