MOLLTTSCA OF THE l CHALLENGER' EXPEDITION". 105 



the deep suture and by the inflated apex. From Q. (T.) hebes, 

 W., its sculpture and its apex distinguish it at once. 

 5. Ceeithitjm mattjkense, n. sp. 



St. 173. July 24, 1874. Lat. 19° 9' 32"-35" S., long. 179° 41' 

 50"-55" E. 310-315 fms. Coral. 



Shell. — A tall, narrow, sharply-pointed cone, somewhat tumid 

 in the last whorl, with little sculpture, but with largish white 

 varices, and beautiful glossy brown spiral threads, speckled with 

 white on a dull translucent white ground. Sculpture. Longitudi- 

 nals — the upper whorls are thickly set with narrow, close, curved, 

 tubercled ribs, which run with a slight twist almost continuously 

 from whorl to whorl ; irregularly, but on nearly each whorl, one 

 of these ribs swells and broadens as a white varix. On the later 

 whorls the ribs are much less marked and the tubercles crowd 

 closely together on the spiral threads ; the varices, too, become 

 larger, and appear at the distance of 1| whorl ; the surface is also 

 thickly set with fine sharpish hair-like lines of growth. Spirals — 

 Besides one in the suture concealed by the succeeding whorl, 

 there are on the small apical whorls 3, but on the last 13 or 14 

 whorls there are 4 narrow well-defined rounded glossy spiral 

 threads ; on the last whorl, in its latter half, one or two more 

 narrower threads aj^pear on the upperside of the whorl ; on the 

 base they are narrower and set more closely, and four or five 

 delicate ones ornament the pillar. On the last whorl especially 

 the upper spirals are studded with close-set small round tubercles. 

 The interstices are about three times as broad as the threads 

 themselves, and are delicately fretted with very fine spiral lines. 

 Colour a translucent white, dead towards the apex, with some 

 irregular brownish stains on the spire, dead-white varices, and 

 brilliant brown spiral threads spotted with white tubercles. Spire 

 tall, conical, and a little bent. Apex sharp but rounded. Whorls 

 20, of very slow and regular increase, scarcely convex, but the 

 last is a little tumid, flattened on the base, but not at all angulated, 

 and bisected by an exceptionally large varix. Suture linear, but 

 with a very slight impression. Mouth nearly semicircular, from 

 the great sweep of the outer lip, and the very slight relative con- 

 cavity of the whole inner lip from the upper corner of the mouth 

 to the point of the pillar; porcellanous within. At its upper 

 angle there is a narrow little corner formed by a slight contraction 

 of the lip towards the body, and by the elevation of the second 

 basal thread into a tooth by a porcellanous thickening at this 



LINN. JOTJRN. — ZOOLOGY, VOL. XV. 8 



