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Show 362 MR. R. B. WATSON ON MADEIRAN MOLLUSKS. [Mar. 18, who have kindly examined it for me, assure me that it belongs to no known genus. From Rapana of Schumacher, which it resembles in its gaping umbilicus, it is well distinguished by its elongated spire and its claw-like operculum. The operculum of Rapana is of the Purpura type. The genus obviously falls under the family Muricidee as so well defined by Mr. Gwyn Jeffreys. CHASCAX MADERENSIS, Watson. (Plate XXXVI. fig. 30.) Body coloured a deep fuscous red. Shell conical, spindle-shaped; as the shell lies on its mouth the periphery in the centre of the back is exactly in tbe middle of the shell's length, the line to the point of the base and that to the tip of the spire being equal; solid, angulated, rough, and opaque ; ribbed and spirally ridged, no varices. With an enormous umbilicus. Outer and inner lip smooth, with a long, straightish, and open, but deep canal. Epidermis horny and brown. Sculpture, 11 to 12 broad, low, rounded, irregular ribs, which scarcely appear above the suture or on the elongated base ; near the mouth they are most broad, rounded, and flattened ; higher up on the course of the whorl they become narrower and sharper ; on the penultimate whorl there are nine. There is nothing approaching a varix or labial rib. There are spiral ridges. In crossing the ribs, these are more or less thrown out into long, narrow, and sharp murications. Of these ridges there are two on the upper whorls, but on the body-whorl there are three, each accompanied below by its shadow ; that of the highest one is double. On the elongated snout-like base there are five or six of these faint ridges or threads, one of them about the middle being a little stronger than tbe rest. Of the three strong ridges, the highest is remote from the suture, and forms a strongly marked shoulder ; it is very decidedly the strongest of the three, the lowest being much the feeblest. Between this shoulder and the suture a few (three or four) very faint spiral threads appear. Besides all these the epidermis is sharply but coarsely wrinkled longitudinally with very slight microscopic spiral striolations. Colour uniform : that of the shell itself is light brownish orange ; but the persistent epidermis is rich yellow-brown. Epidermis a strong, horny, close-fitting, adhesive membrane. Spire long, rising in steps, contracting regularly but rapidly to a narrow, small, and very sharp apex. Whorls 6 to 7, angular, sloping downwards from the suture with rather a longish shoulder, and from the point of the shoulder dropping perpendicularly, i.e. parallel to the axis of the shell. The upper whorls have no contraction on their lower side, as the suture runs close below the second spiral ridge; on the body-whorl, however, there is a great contraction below the third spiral ridge ; and beneath this contraction the base advances downwards in a long and very little-attenuated snout, which includes the canal and the enormous umbilicus, round which the shell runs in a great fold. Suture slight, rough, and (apparently) slightly channelled, some- |
