Cerion eleutherae Pilsbry and Vanatta, 1896

Original Description

"Shell solid and strong; smoothish above, ribbed below; color lusterless; white, with a bluish-purple tint, most obvious around the base, cylindric-tapering, terminating above in a rather long slightly convex-sided cone which passes gradually into the cylindrical por­tion. Apex obtuse; whorls 10½  to 12½; nepionic 2½ whorls nearly smooth, slightly convex; following whorls of the cone smoothish to the naked eye, showing rather irregularly spaced wrinkles under the lens, flat, with seam-like sutures, not in the least impressed.  Latter 4 whorls approaching equality in diameter, suhregularly and rather strongly costate (at least the lower two whorls), the last one with about 27 (22 to 30) ribs, which do not split or double on the base, although sometimes there are some riblets intercalated there.

            Aperture about one-third the shell's length, oblong or rounded, obliquely truncate above, liver-brown within. Peristome white, re­flexed, the outer edge sharp and somewhat recurved, inner edge built far forward, especially below, bevelled outwardly; parietal callus either very thin or thick. Axial fold variable in prominence; parietal tooth very strong, long. Axis perforate, with a rather short rimation.

Alt. 29, diam. 11½ ; alt. of aperture 11 mm.

Alt. 33, diam. 11; alt. of aperture 11 mm.

Alt. 23½, diam. 11; alt. of aperture 9 mm.

Eleuthera, Bahamas.

            This species is closely allied to C. Agassizi Dall and C. guberna­torium Crosse, of the island of New Providence. It has more remote affinity with C. sarcostomum P. & V. of Little Inagua.

            From C. Agassizi it differs in never having the parietal callus raised in a strong ridge making the peristome continuous; the ribs are less sharp and narrow, etc. C. gubernatorium has a proportion­ally very large mouth, less thickened lip, finer riblets or none, and a glossy surface; moreover, while nearly white examples occur, it is generally much variegated. There can be no doubt of the close relationship of the three species, but judging from a series of 25 examples of C. Eleutheræ, a good series of C. gubernatorium and author's examples of C. Agassizi, they are specifically distinct.

            A pair of specimens of C. Eleutheræ before us (from Krebs) are considerably streaked with brown, otherwise typical. Another spec­imen, received from Mr. Van Nostrand, is very small, att.18⅔, diam. 8 mm., and somewhat maculated. The costulation extends further up, and the peristome is not thickened. This probably represents a subspecies."

(Pilsbry and Vanatta, 1896:333-334).


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