318 THE VOYAGE OF H.M.S. CHALLENGER. 



middle of each whorl is a row of tubercles, which stand out on the upper whorls rather 

 sharp and rounded, but on the lower whorls are elongated into slight, oblique ribs, which 

 tend to become obsolete on the last whorl, and do not extend to the base. They are 

 parted by shallow rounded furrows, which are a good deal broader than the ribs. There 

 are about thirteen of these on each whorl ; they do not extend in the least to the sinus- 

 area above the tubercles. The surface is very closely scored with coarsish lines of growth. 

 Spirals — the line of the tubercles forms a rather acute carination, of which there is hardly 

 a trace in the curve of the whorls themselves. The whole surface is covered with harsh, 

 unequal, irregular, flatly rounded threads, which are cut into small coarse granulations by 

 the lines of growth ; this sculpture is most developed on the base and snout, less so in the 

 sinus-area, least so of all on the rib-area. Colour buff below the yellow epidermis, which 

 is coarse and harsh, but not thick ; the surface of the shell below it is smooth and free 

 from the granulated texture, but is curiously reticulated by miuute interrupted wrinkles, 

 whose course is at right angles to the lines of growth. Spire high and conical ; its 

 profile-lines are little interrupted by the contraction of the suture. Apex eroded in all 

 the specimens. Whorls 10 to ll(?), of regular, rather rapid increase, shortish, with a 

 largish, sloping, but hardly concave shoulder above and a very slight contraction below. 

 They are arigulated by the projection of the line of tubercles, but are otherwise little 

 convex ; the last is a little tumid and considerably elongated, a little contracted on the 

 base, and gradually drawn out into the conical, straight, longish, and at the end smallish 

 snout. Suture rather deep, and strongly marked by the angle at which the superior and 

 inferior whorls meet. Mouth buff-coloured within, rather long and narrow, pear-shaped, 

 pointed above, with a longish, broad, and open canal below : the direction is very little 

 oblique. Outer Up curves pretty equally from its origin to the edge of the canal, from 

 which to the point of the snout its course is nearly straight : on leaving the body it 

 retires at once, but very slightly and regularly, so as to form the shallow and openly 

 rounded sinus, from which it advances with a long and regular sweep to the front of the 

 mouth, and then curves slowly backward to the point of the snout : it is thin throughout ; 

 above it is straight, but lower down a little patulous. Inner Up spreads rather broadly 

 across the pillar, highly polished, buff-coloured, with a slightly raised edge; it is very 

 little concave above, straight but rather short on the pillar, which is cut off to a long fine 

 point, with a blunt, rounded, very slightly twisted strongish edge. H. 175 in. B. 0*68. 

 Penultimate whorl, height 0'26. Mouth, height 0'85, breadth 0*45. 



This species has a vague general resemblance to Pleurotoma sanctijohannis, E. A. Sm., from 

 Japan ; but that is not ribbed, and has a much longer mouth. Judging by the figures (see Lischke, 

 Japan. Meer. Conch., pt. 3, p. 22, pi. i. fig. 1, and "Weinkauff, Conch. Cab. (ed. Kiister), p. 51, 

 pi. xi. fig. 5), it is a good deal like Pleurotoma kadcrleyi, Lischke, but is smaller, considerably less 

 elongated, and very different in colour. It has a very considerable resemblance to two Eocene Pleuro- 

 tomas, viz., Pleurotoma selysii, Koninck, and Pleurotoma nodulosa, Lam., between which it occupies 



