Shell large, robust, and dull beige. The apex is dissolved in all specimens, only 2.5 whorls remain. One strong spiral keel commences in the suture of the oldest preserved whorl, then moves further away from the suture and ends up forming a distinct peripheral shoulder. A second spiral rib emerges from the suture half a whorl after the first one and forms a less strong keel near the suture. A third spiral keel is concealed under the suture and visible only on the body-whorl. Except for these keels the surface has some growth irregularities, which form growth complete lines only at the outer lip. The aperture is tangential and strongly prosocline. The columellar callus is thin, and there is no umbilicus. Dimensions. Diameter of holotype 14.4 mm Operculum: Diameter 6 mm. The external surface is indistinctly granular, without spiral pattern. The internal surface is distinctly spirally coiled and covered by a well-developed corneous layer. Radula: The radula is rather long with about 100 transverse rows. The normal turbinid sigma shape (see Hickman & McLean 1990, figs 20, 26) with a 'dip' in the central part of the transverse rows is not strongly pronounced. The marginal teeth are slender, about 35 in number, and have a simple, smooth apical plate. A sturdy lateromarginal plate is formed by the base of the innermost marginal tooth. Five lateral teeth, the more central ones having more sigmoid shafts. The lateral side of the cutting plate has a few small denticles. The central tooth is large and ovate and has a part of the triangular cutting plate left from the larval radula.

This new species of Cantrainea differs from other species known to us by having fewer spiral keels [four or more in other species, including the Caribbean Lepthothyra philipiana Dall, 1889, C. indica (E. A. Smith, 1894) from the Indian Ocean and C. bicarinata (V. Martens, 1904) off South Africa, which all have a super¬ficial resemblance].

Louisiana Slope. Hydrothermal vents.