56 G THE VOYAGE OF H.M.S. CHALLENGER. 



thread ; at the top of the pillar is another finer ; on the pillar itself there are two folds. 

 Colour pale brownish, with darker stains. Spire high and narrow, conical. Apex conical, 

 consisting of five rather sharply angulated and carinated whorls, which are ornamented by 

 minute not quite regular longitudinal bars ; the extreme tip is small, rounded, quite 

 smooth, polished, and not very prominent, but rather spread out than immersed. Whorls : 

 there are 11^ regular whorls, wdiich are short and of very gradual increase; the edge of the 

 base is bevelled off, but the base itself is flat, with a slight hollowing in the middle. 

 Suture furrowed, but in itself invisible, rather oblique. Mouth somewhat squarely rounded, 

 small, bluntly pointed above. Outer lip is very thin and sharp ; has at its insertion a 

 small deep rounded sinus, below which it advances very much into a scoop-like form on 

 the base, and is on the right sharply bent in upon the pillar, the forward edge of which it 

 inwraps. Pillar very short indeed; its point is twisted, and very sharply bent to the 

 right, infolding the generic canal. Inner lip concave, very short, with a thickened edge ; 

 there is a minute nick at its junction, with the outer lip on the pillar. H. 0'184 in. 

 B. 0-048. Mouth, height 0-027, breadth 0-022. Apex, height 0-018, breadth 0-013. 



This species is not at all unlike the smaller forms of Tri/oris perversa (Linne), of Europe ; but, 

 besides very many minute points of distinction, the base is squarer, with two not three threads, the 

 labral sinus is much deeper, the mouth is rounder, the basal lip more produced, and the pillar tip more 

 bent and elongated ; the sutural furrow, too, is deeper, wider, and less oblique, and while the apes 

 is slightly broader, the extreme tip is a very little smaller. 



7. Tri/oris rufula, 1 n. sp. (PI. XLII. fig. 2). 



Station 186. September 8, 1874. Lat. 10° 30' S., long. 142° 18' E. Off Wednesday 

 Island, Cape York, North-east Australia. 8 fathoms. Coral mud. 



Shell. — High, ruddyish, with convexly conical outlines, a slightly convex base, three 

 rows of tubercles on each whorl, a small furrowed suture, and a conical and high apex. 

 Sculpture: Longitudinals — there are on the last whorl about 18 (on the earlier whorls 

 fewer) direct riblets, which run down the spire pretty continuously, and cross the base ; 

 the parting furrows are wide open and rounded. Spirals — on each whorl there are three 

 very slightly raised square threads, which swell into strongish tubercles as they cross the 

 riblets ; they are parted by squarish somewhat narrower furrows ; at the angle of the 

 base, barely within its contraction', is a slightly weaker subtubercled thread ; another, 

 weaker and undulated rather than tubercled, occupies the middle of the base ; round the 

 top of the pillar is another weaker still. Colour yellow, more or less ruddy. Spire high, 

 very slightly tumid, the lateral outlines being convex. Apex has a small blunt rounded 

 tip, is translucent white and conical, and consists of five short convex whorls, on each of 

 which, above the middle, are two fine flat slightly raised threads ; their surface is also 



1 So called from its colour. 



