MOLLUSCA OF THE ' CHALLENGER ' EXPEDITION. 219 



cially those toward the base of the whorls are so. The micro- 

 scopic spiral frettings, which are distinct from these and very much 

 more minute, are present, but want sharpness. The upper 

 whorls are smooth and polished. Colour yellowish, more or less 

 tinged and speckled with brown and white. The white is 

 strongest toward the top of the whorls and is in suffused patches; 

 the brown, which also occurs in suffused patches, is prettily 

 dotted in minute specks on the spiral threads. The colour 

 pales on the upper whorls ; but the apex is yellow. Spire very 

 perfectly conical, though the contour-lines are interrupted by the 

 projection of the inferior carina and by the impression of the 

 suture. Apex very fine and small, but rounded, the extreme tip 

 being a little depressed on one side and the first whorl towards 

 its end projecting a very little beyond the second. Wliorls 15, 

 almost flat, with a constriction between the two carinas, narrowed 

 gradually upwards, but more quickly into the inferior suture 

 roundly angulated at the basal edge, with a flattish base which 

 is but feebly conical. The last four or five whorls are higher 

 proportionally than the earlier, which are of very slow and 

 gradual increase ; the first two are markedly smaller than those 

 which follow ; all the earlier whorls are distinctly convex. 

 Suture fine, but distinct. Mouth rather small, almost square, 

 but a little higher than it is broad. Outer Up very straight, roundly 

 angulated below, patulous and almost canaliculate at the pillar- 

 point ; it advances a good deal at its junction with the preceding 

 whorl, from which point it retreats so as to form a very deep 

 and narrow sinus, the upper edge of which lies along the 

 upper carina, and whose apex occupies the depression between 

 the upper and lower carina. The lower edge of this sinus ad- 

 vances in a line much more oblique than its upper edge, which 

 is almost parallel to the suture ; it is the deep curve of this sinus 

 which bends the lines of growth into so strong a curve as they 

 cross the whorls. Inner Up is spread across the body as a thin 

 glaze ; it thickens a little toward the base of the pillar, round 

 and behind which it spreads, so as to leave a minute umbilical 

 pore. Pillar is very straight in the line of the axis, but is bent 

 backwards more than is usual in the genus; its edge is narrow, 

 rounded above, with a brilliant milky gauze, slightly reverted and 

 sharp below, and ending in a fine point. H. 1"25. B. 0'4, 

 least 0-38. Penultimate whorl, height 018. Mouth, height 

 028, breadth 0*22. 



LINN. JOLBN. — ZOOLOGY, VOL. XV, 17 



