Shell very elongated, angle less than 10°, composed of eighteen or possibly more elevated, squareish whorls, which slightly diminish in convexity in descending the spire; apex acuminate (Plate IV. Fig. 4); ribs ten or eleven, straight or slightly sinuous, linear near the apex, but becoming more prominent and obtuse with the growth of the shell, the intervening spaces nearly flat. The ribs, in common with those of other Cretaceous Scalidæ, are never so clean and sharp as in the recent species, but have more the appearance of folds. In some of the larger specimens the ribs disappear altogether on the last three or four whorls, and are represented only by more or less strongly marked lines (Plate IV. Fig. 1). The striæ are fine and numerous (Plate IV. Fig. 1a), fifty or sixty on each whorl. The sutures are very distinct, the margins of the whorls being usually raised into a roll-like collar. This collar appears on the last whorl in the form of a conspicuous spiral keel, against which the ribs terminate, leaving the base of the whorl, which is very flat, marked with striæ and lines of growth only. The aperture is oval or quadrate, and in the perfect state was probably terminated anteriorly in a sort of beak (Plate IV. Figs. 2 and 3); lips thin!; columella smooth. The cast of the shell generally preserves the rib marks, except near the apex, where the whorls are smooth and very rounded.