Turn'*.] GASTROPODA. 471 



it is feeble. Between the keel and the superior suture lie 3 very fine 

 equally parted threads. On the base and neck of the canal are about 

 12 pretty equal tine threads. Colour a faintly yellowish-grey. Epi- 

 dermis extremely thin, smooth. Spire conical, with an almost un- 

 broken profile, the whorls being scarcely convex. Protoconch of barely 

 2 whorls, smooth, globose, not flattened down at the tip, which, how- 

 ever, is slightly immersed. Whorls 7, feebly keeled, with a just per- 

 ceptibly concave line from the suture to the keel, and from the keel 

 to the suture below. Just above the suture there is a slight contrac- 

 tion, which forms a faint superior margination. The last whorl is 

 very slightly swollen ; the base is rather rapidly contracted, and is 

 drawn out into a rather long, straight, but not narrow canal. Suture 

 distinct, impressed. Aperture almost club-shaped, being pointedly 

 oval above, with a longish rather sinuous canal below. Outer Up 

 forms a regular curve, till at the canal it becomes flattened and oblique ; 

 from the body it retreats at once to form the rather deep rounded 

 open-mouthed sinus, from which it advances on a very straight line 

 to the edge of the canal in front, where it bends slowly and slightly 

 backwards ; it is throughout open, but not patulous except at the 

 point of the canal. Inner Up spreads as a narrow porcellanous glaze 

 on the body and pillar ; it is slightly hollowed out on the body, is 

 straight on the pillar, toward the front of which it is cut off with a 

 narrow rounded and very slightly oblique edge. (Watson.) 



Diameter, 2-25 mm. ; height, 8-5 mm. 



Animal unknown. 



Type in the British Museum. 



Flab. East of East Cape, in 700 fathoms (" Challenger "). 



Subgen. 2. LEUCOSYRINX, Dall, 1889. 



Leucosyrinx, Dall, Bull. Mus. Cornp. Zool., xvii, 1889, 75. Type : Pleurotoma 

 Verrillii, Dall. 



Shell white or pale without colour pattern, thin, the anal notch 

 behind the periphery or at the suture ; sculpture delicate, of spiral 

 keels or threads, and often oblique riblets on the shoulder of the 

 whorls : peripheral keel, if present, not recurved. Operculum thin, 

 nucleus apical, scar of attachment small. 



Larval shell glossy, rounded or keeled ; other shell-characters as 

 in Tunis. 



This group is intended to contain the operculated species of Turris 

 (in its widest sense), which are so characteristic of the archibenthal 

 region. They are distinctly contrasted with the coarse, spotted or 

 maculated shallow- water species of Turris proper by their thin, 

 white, delicately sculptured shells. The anal notch is generally wide, 

 more rounded, and nearer the suture than in typical Turris, and the 

 operculum proportionally wider and more delicate. 



All species from deep or comparatively deep water. 



