MOLLUSCA OF THE ' CHALLENGES ' EXPEDITION. 467 



riblets, whose obliquity increases on each successive whorl : the 

 lines of growth, which are quite independent of the riblets, are 

 very slight. Spirals — there is a row of quite separate, very small, 

 elongated tubercles below the suture : the sinus-area is bordered 

 on its lower side by a very faint and small furrow : the angu- 

 lation of the whorl below this is chiefly due to the row of beads 

 in which the ribs originate, and here there are several very 

 minute threads : 9 somewhat stronger, equal, and equally parted 

 threads occupy the body from this angle downwards ; about 5 

 others, stronger and wider apart, occupy the base, and about 4 

 more the snout ; here and there a much finer thread occurs in the 

 intervals. Colour white. Spire high, subscalar, conical. Apex 

 small, high, conical, with tumid whorls ; the sculpture is typical, 

 i. e. with straight bars above and obliquely reticulated ones below ; 

 the two or three of the very tip are broken. Whorls 6-7, exclu- 

 sive of those which form the apex, of regular increase, with a 

 drooping concave shoulder, keeled, and below the keel almost 

 cylindrical, but with a very slight contraction to the lower suture ; 

 the last whorl is short, tumid, with a rounded base produced into 

 a short, broad, triangular, one-sided snout. Suture very slightly 

 impressed and extremely small, as the inferior whorl laps up on 

 the one above it. Mouth angularly oval, pointed above, broad in 

 the middle, and obliquely prolonged below into the short canal. 

 Outer Up concave in the sinus-area and angulated at the keel ; it 

 forms from this point a very regular curve to the front : the edge, 

 which sweeps far out below, forms rather a low shoulder above, 

 between which and the body lies the deep, rather narrow, open- 

 mouthed, rounded sinus. Inner lip is excavated, has a slight 

 raised border outside of it, is rather broad, and continues to the 

 extreme point of the short narrowish pillar, which is rather 

 obliquely cut off with a rounded twisted edge, and whose 

 junction with the body is deeply concave. H. 054. B. - 24. 

 Penultimate whorl, height 0"1. Mouth, height - 24, breadth 

 0-13. 



This species has some resemblance to one which Dr. Grwyn 

 Jeffreys got in the ' Porcupine ' dredgings from 994 fathoms, 

 and in the ' Travailleur ' dredgings in the Bay of Biscay, and 

 which he proposes to call Defi-ancia forniosa — a name with this 

 disadvantage, that there is already a Pleurotomaforwiosa of Beeve. 

 In the ' Challenger ' expedition it was got at St. 24, St. 73, St. 78, 



