Cerion basistriatum Pilsbry and Vanatta, 1895

Original Description

"Shell rather thin, cylindrical, the latter three whorls of about equal diameter, those above tapering- rapidly, forming a straigbt­sided cone about one-third the shell's length. Surface rather smooth and glossy. Two corneous nepionic whorls smooth; succeeding one or two turns densely and regularly striated; rest of the shell smouth except for slight irregular growth-wrinkles, down to the last whorl, which is finely costulate. Color white with irregular longitudinal streaks and blotches of brown. Whorls 9, hardly convex, the last ascending slowly in front, rounded below, with a short umbilical rimation. Aperture about four-tenths the shell's length, rounded­ovate, nearly as wide as high, brownish within.  Peristome thickened, outer lip expanded but scarcely reflexed, columellar lip reflexed;  the terminations connected across the parietal wall by a strong, elevated callous ledge. Axial lamina small as seen from the mouth; parietal lamina small, often double, moderately long; a small denti­cle to the left of, and an elongated lamina behind and to the right of its inner end.

Alt. 18, diam. 9; apert., alt. 7, width 6½ mm.

Alt. 16½ , diam. 8; apert., alt. 6, width 5½ mm.

Cabo Cruz, Cuba.

This species differs from G. tridentatum in its round aperture with strong parietal callus, and the costulate basal volution; from C.  striatellum it differs in the much smoother surface, thinner substance, etc. The arrangement of parietal plicæ is of the same type as found in the two species mentioned." (Pilsbry & Vanatta, 1896:335-336)

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