HYDRUS SCHISTOSUS, (Daudin.) SYN.*-Russell, II, Pl. 10, Hooglí Pattee, 1801. Hydrus valakadyen, H. Boie, 1827. Hydrophis, apud Wagler, 1830. Leioselasma schistosa, Fitzinger, 1827. Hydrus, apud Wagler, 1830. Hydrophis schistosa, Schlegel, 1837. Hydrophis schistosa, Schlegel, apud Cantor, 1. c. New born.-Head above blackish or dark brown; back and sides with numerous transversal blackish bands, broad above, narrow on the sides; lips, throat, sides and abdomen buff; tail blackish with a few transversal buff bands above. Entire length 10 inch. Adult?-Head above and back either uniformly pale greenish grey, or with darker transversal bands, becoming more or less indistinct on the sides; lips, throat, sides brownish white or buff; tail uniformly blackish, or greyish olive-green. Iris pale amber or greenish-yellow, with a grey orbital margin; pupil black, tongue buff. Central abdominal series: 239+47; 242+42; 312+58. HABIT.-Sea of Malayan Peninsula and Islands. Bay of Bengal, Malabar, Sumatra. The head is elongated conical, the muzzle sloping and the rostral shield beneath terminating in a vertically projecting point, which fits into a corresponding cavity in the lower jaw. The anterior elongated triangular frontal shields are next to the occipitals the largest; the large oval nostrils send a slit towards the external margin of the shield. The eyes are lateral, moderate, surrounded by a præ-orbital, a post-orbital, frequently cut in two smaller, and beneath by the fourth upper labial shield. Behind the latter, the lip is covered by three or four horizontally placed small shields, above which appear three large vertically placed shields, of which the last borders the sides of the occipital pair. The lower rostral is remarkably elongated, linear, and hid in a furrow between the first pair of inferior labials. Of the latter the anterior five on each side are much elongated, followed by five or six smaller. The chin is covered with numerous minute scales, and like * DOUBTFUL SYN.-Hydrus major, Shaw, 1802.-Disteira doliata, Lacépède, 1804. the rest of the body with very lax skin. In the young ones the neck is covered by 47, the bulkiest part of the body by 57 longitudinal series of smooth, somewhat tubercular scales. Older individuals have these parts covered by 48 and 60 series of hexagonal scales, either with a short keel dividing the anterior half, or a central tubercle. The central, slightly raised, abdominal series commences very far back, from one to three inches behind the chin. The anterior scales are wedgeshaped hexagonal, the posterior are broader, but slightly larger, than the rest, with a small elongated tubercle on each side. The largest individual of a great number, was of the following dimensions : Circumference of the neck, 23, greatest do. of the trunk, 5 inch. HYDRUS PELAMIDOIDES, (Schlegel.) SYN.*-Pelamis carinata, Cuvier, MS. Hydrophis (Disteira doliata, Lacép.) Wagler, 1830. Hydrophis pelamidoides, Schlegel, 1837. Hydrophis pelamidoides, Temminck and Schlegel, Fauna Japon. Tab. 9. Young. Sulphur coloured, paler on the sides and abdomen; the head largely spotted with blackish, through which the ground colour appears in the form of a rectangle, the two sides of which pass from the hindhead to the orbit, the anterior across the frontals, the posterior over the hind-head; two yellow spots between the nostrils; lips yellow, cheeks and throat blackish; on the back a number of transversal blackish bands to the middle of the sides, broader than the intervening yellow lines; tail black. Entire length 10 inch. Adult?-Head uniformly reddish brown above; ground colour greenish yellow, lighter on the sides and beneath, with broad lozenge shaped transversal bands of a blackish olive, continued on the anterior half of the tail; posterior half blackish. Iris dark olive; pupil black; tongue buff. * DOUBTFUL SYN.-Russell, II, Pl. 12, Shiddil, 1801.-Hydrus curtus, Shaw, 1802. HABIT.-Sea of Malayan Peninsula and Islands. Bay of Bengal, Sea of Celebes, Molucca Islands, China Sea. The head is much depressed, not broader than the neck; the muzzle broad, rounded; the rostral shield is large, rectangular pentagonal, broader than high, the lower margin with a central point and a notch on each side. The eyes are moderate, lateral, not prominent, surrounded by a præorbital, a post-orbital, and beneath by the third and fourth upper labials. The frenal shield, observed by M. Schlegel, was not present in four individuals, examined in the straits of Malacca: its existence therefore appears not to be constant: in all Hydri the shields of the head are liable to considerable individual variations of form. Of the eight upper labials the posterior three are very small, which is also the case with the posterior five of the nine inferior labials. The two pairs of elongated mentals are outside bordered by the three first inferior labials, inside, by several small scales. In the young the neck is covered by 37, the thickest part of the trunk by 40 longitudinal series of hexagonal, smooth, comparatively small scales. In the older individual these parts are covered by 32, and 37 large hexagonal scales, each with a central tubercle. The lower series of the sides are slightly larger than the rest, and vertically elongated, so as to acquire a rectangular appearance. The central abdominal series is much smaller than the rest. Each scale is either rhombic, and, as represented in the excellent plates of Fauna Japonica, hemmed in between four* of the two lowest lateral series, or they are absent, and their place is occupied by a pair of the former, which are soldered together. In young individuals the central series frequently consists of alternate broad triangular, and very minute rectangular scales, both kinds smaller than the rest. The largest individual of four was of the following dimensions: Circumference of the neck, 21, greatest do. of the trunk, 4 inch. A somewhat similar disposition is observed in the central dorsal series of the however differently shaped scales of Xenodermus juvanicus, Reinhardt. HYDRUS BICOLOR, Schneider. SYN.-Seba, II, Tab. 77, Fig. 1. Angvis platura,* Linné, 1766. Vosmaer: Monogr. Fig. 1. 1774. Angvis platuros, apud Gmelin, 1788. Russell, I, Pl. 41. Nalla Wahlagillee Pam. 1799. Hydrus bicolor, Schneider, 1801. Hydrus bicolor, apud Shaw, 1802. Pelamys (Angvis platura, Lin.) Wagler, 1830. Pelamis bicolor, apud Horsfield, Life of Raffles, 1830. Pelamis bicolor, apud Oken, 1836. Hydrophis pelamis, Schlegel, 1837. Hydrophis pelamis, Temminck and Schlegel, Fauna Japonica, page 60. Head and back black (inky), forming a straight line on the sides till towards the posterior part, where it becomes largely undulating, so as to appear as broad bands; lips, throat and sides sulphur coloured, turning into yellowish white or buff on the abdoment and tail; posterior parts of the sides with some more or less distinct rounded black spots; tail largely banded or spotted with black. Iris pale yellow with a broad black orbital margin; pupil black; tongue buff. HABIT.-Sea of Malayan Peninsula. Bay of Bengal, Malabar, Sea of Sumatra, Java, Celebes, Molucca Islands, China Sea (to 27° N. Lat.) Otaheite, Bay of Port Jackson (33° 55′ S. Lat.-151° 25' E. Long.) The head is very elongated, depressed, viewed from above, it presents a striking resemblance to Herpetodryas oxycephalus (Reinwardt). The eye is larger than in any other species of Hydrus, surrounded by two, three, or even four post-orbitals, one large præ-orbital, and beneath, by the fourth upper labial shield. A frenal shield has been observed in some individuals, but it was absent in that examined in the straits of Malacca, nor does it exist in the specimens, in the Museum of the Asiatic Society. The neck is covered by 44, the thickest part of the trunk by 52 longitudinal series of small scales. Those of the upper parts are smooth, hexagonal; those of the sides approach the orbicular form, and have in the centre one, two or three longitudinally placed * In consequence of the specific name of Linné having been applied by Latreille to a genus (Platurus), that of Schneider, the next different in succession, has been substituted. + In the individual figured by Russell, the bright yellow colour formed a narrow lateral line, below which the sides and abdomen were of a dusky greenish yellow. minute tubercles. Similar tubercles are observed on each side of the scales, forming the central abdominal series, which is composed either of entire hexagonal scales, a little larger than the rest, or they are longitudinally divided into pairs of smaller pentagonal scales, which have the appearance of being divided by an abdominal suture. A single individual taken in a fishing stake, off the coast of Province Wellesley was of the following dimensions : Circumference of the neck, 24, greatest do. of the trunk, 3 inch. The preceding, comprising all the hitherto known species of pelagic serpents were observed chiefly at Pinang, among the abundant supply of fishes, daily carried to the markets. Of their general habits some account appears in the Transactions of the Zoological Society, London, Vol. II, p. 303. One of them, Hydrus schistosus, is incredibly numerous in the Bay of Bengal, at Pinang and Singapore, far more so than any known terrestrial serpent. The fishing nets are hardly ever worked, but that one or more are among the contents. The other six species are of rare occurrence at Pinang and Singapore, as will be perceived from the disproportionally small number of each, examined during four years, viz. of Laticauda scutata : 3; Hydrus striatus: 2; nigrocinctus : 6; gracilis: 7; pelamidoides: 4; pelamis: 1.-Of these Laticauda scutata is excessively numerous in Timor, Hydrus pelamis in New Guinea, the Molucca Islands, and Otaheite, where the natives use it as an article of food. The remaining species, as far as is known, have been observed nowhere in such overwhelming numbers. Large individuals of every species are very seldom seen, it is the young individuals which frequent the coasts, and it appears to be questionable, if even the largest observed are animals arrived at their full size. The large individuals are very ferocious; the young ones are less so. Fortunately for the fishermen the light blinds these serpents, which when out of their proper element, become very sluggish and soon expire. This accounts for the safety of the class of men, whose daily calling brings |