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. 



<7jih Chascax maderensis, Watson. (Plate XXXVI. fig. 30.) 



' >Cf5i 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 the 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 the 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- 



