Cerion acherontis sp. nov.

Figures 1, 2

Description-Apex and an unknown number of early whorls missing. Shape of last four whorls (the only ones preserved) elongate-ovate; first three whorls gently expand­ing, broader at base than at summit, the fourth contracting to a produced, smoothly curved base without peripheral keel or angulation. Whorls of spire flat-sided to very weakly convex, neatly appressed at suture to previous whorl, with narrow, shallow sulcus (barely visible on first preserved whorl but quite prominent by penult and body whorl) just below suture and paralleling it. Surface of whorls generally smooth but with low, irregularly spaced, retractive growth rugae, strongest on posterior third of whorl but fading out before reaching suture. Growth rugae weakly convex-forward posteriorly, straight for most of their length. Anterior edge of spire whorls sharply angulate, turning under abapically to nearly flat base, in some places weakly overhanging summit of following whorl. Body whorl with same surface character as preceding whorls; base not umbilicate. Peristome adnate to face of body whorl (only columellar and part of parietal lip preserved); columellar lip thickened, smoothly rolled outward; parietal callus thin.

Diameter (shell flattened in matrix) 12.8 mm; height 19.9 mm; height of last whorl 11.2 mm.