MOLLT7S0A OF THE ' CHALLENGER ' EXPEDITION. 267 



course, and retreat rather strongly so as to become horizontal as 

 they die out on the pillar ; they are parted by shallow flat fur- 

 rows of unequal breadth, but greater than that of the ribs ; 

 over the whole surface, but especially in the furrows, are sharp 

 puckerings with finer folds between, and close-set, sharp, almost 

 microscopic stride in the lines of growth ; on the upper whorls 

 the ribs are fewer and sharper. Spirals — on the last whorl there 

 are 13 broad, low, squarish, raised bands, which are narrower and 

 sharper on the snout : the first is at the suture; the second, a little 

 remote, is narrower, but sharper than the rest ; this and the third 

 rise on the longitudinal ribs to high, narrow, sharp spikes which 

 are parallel to the axis of the shell ; the lower row of these is the 

 larger, and they give the appearance of a shoulder : the spirals 

 are most squarely prominent on the ribs, but are faintly continuous 

 in the intervals ; they are parted by square furrows of the same 

 breadth as themselves; the surface of the shell is also finely 

 scratched : below the spiral bands is a broad low swelling which 

 curves round the pillar ;] it indicates the old canal, the former con- 

 cave lines of whose edge form strong scores across it. Colour pale 

 buff, with faint chestnut mottlings, which are concentrated and 

 darkened in two distinct deep-purple bands in the middle of the last 

 whorl, with fainter traces of two more below and another above 

 near the suture ; all these are vague in their limits. Spire raised, 

 conical, scalar. Apex small, consisting of 3| embryonic whorls, 

 which are polished, turbinated, and end in a fine, round, 

 raised point; they are slightly iridescent ; where they join the 

 normal whorls there is indication of that thickening of the lip 

 which is common in the embryonic shell of Cassis. Whorls (on 

 the not quite adult specimen) 8, exclusive of the embryonic whorl ; 

 they rise high and constrictedly on each previous whorl, of which 

 they leave but little uncovered ; they are of very slow increase, 

 the last is very little tumid, and that almost entirely above, its 

 greatest breadth being at the third spiral ; still they are convex 

 throughout till near the point of the base, when the contour-line 

 is slightly hollowed in passing over to the prominent but not 

 lengthened nor narrow snout. Suture is a fine, angularly im- 

 pressed, irregular line, much disturbed by the buttress-like ribs. 

 Mouth long and narrow (but immature), pure porcellanous white 

 within, but stained with the purple bands. Outer lip leaves the 

 body at a right angle, but turns almost immediately to run parallel 

 to the axis, thus forming a short narrow canal ; from this point it 



