Hoplocephalus. Cuv.

Hoplocephalus nigrescens. Gthr.

Black-backed Hoplocephalus.

Scales in 15 rows.

Ventrals 173 to 176.

Anal entire.

Subcaudals 37.

Scales in 15 rows, 6 upper labials, the second of which is pointed above, the third truncated. Uniform bluish grey or purple black above; ventral shields whitish, blackish on the page 48 sides. Description:—Body rather elongate, rounded; tail somewhat short, not distinct from trunk; head oblong, depressed, not distinct from neck; eye small, pupil sub-elliptical. Rostral shield, very broad and low, and very obtuse superiorly; anterior frontals moderate, broader than long, rounded in front; posterior frontals rather large, five-sided, each with two hinder edges forming together a right angle; vertical, six-sided, about as broad as long, with parallel outer edges, an obtuse angle in front, and a pointed one behind; occipitals oblong, obtusely rounded behind; superciliary moderate; two posterior oculars, one anterior just reaching to the upper surface of the head; the post frontal, nasal, anteorbital and second upper labial meet at a point and replace the loreals; six upper labials: the first is very low, situated below the nasal, the third and fourth enter the orbit; front series of temporals formed by two shields, one of which is in contact with the post orbitals. Chin-shields of nearly equal size, several scales between the hinder chin-shields and the first ventral; the median line of the upper part of the tail is occupied by a series of hexagonal scales; a series of small teeth behind the grooved front tooth.

The present species is subject to considerable variation of colours during the course of the year; sometimes before changing its skin the back and head are of a leaden hue, and the ventral scales uniform whitish; after the old skin has been cast off, the upper coat assumes a shining deep purple or bluish black; the ventral scales are at this time rose-coloured, which hue is invariably lost in spirits. The ventral scales of many subjects examined I found clouded on the sides; sometimes the greater part of the scales, in particular those near the vent, were blackish, and the subcaudals entirely so. I believe that this is the only snake of the genus Hoplocephalus in which the tongue is white.

The rocky neighbourhood of Middle Harbour (Port Jackson) is the locality where I first found this new species, but since then specimens have been obtained from Port Macquarie and the Clarence River, which do not differ in colour from those inhabiting the neighbourhood of Sydney; it is highly probable that the geographical distribution of this species extends still farther to page 49 the northward; but, owing to its nocturnal habits, collectors will experience great difficulty in capturing it.

During the cold season, from May to September, I have frequently found this Snake hybernating (if I may so express their dormant state) under loose flat stones, singly or in pairs, but never in company with other Ophidians; and more than once a dozen specimens were the result of a day's hunting.

It is very singular that no Snakes of this kind were ever met with between Sydney and Long-Bay, or towards the South-head, and I believe that they never frequented that district, otherwise the species would have been known long before this, as even White, in his Voyage to New South Wales, figures such rare Snakes as Vermicella annulata, and Hoplocephalus variegalus.

With regard to its habits, I may mention that it is strictly nocturnal, feeding on the smaller Batrachians, as Pseudophryne australis, and Uperoleia marmorata, specimens of which I have found in its stomach. It is rather sluggish in its disposition, and, though venomous, not dangerous to man or the larger animals.

The female produces about 20 young annually.