Strophiops (Strophiops) plegmatum Dall, 1905

Original Description

"Cerion (Strophiops) plegmatum new species. Pl. LVIII, fig. 5.

Shell of moderate size, light and thin, subcylindric, with two and a half polished, pale, latterly microscopically reticulate whorls, fol­lowed by seven smooth or feebly striated whorls axially striped or  clouded with dark or light brown and opaque white. Umbilicus closed, base attenuated, apex rather pointed; peristome thin, simple, yellowish white, broadly reflected, in the adult continuous over the body; parietal laminae short, compressed, axial lamina low, inconspicuous; the base of the last whorl sometimes strongly axially striated.

            Height of

                shell                        Aperture.               Max. Diameter.

                18.5                         6.0                           8.0 mm.

                22.0                         7.0                           9.0           "

                26.0                         8.0                           8.0           "

Numerous specimens were collected by Dr. J. J. Brown of Sheboy­gan, Mich., at Exuma Island. U. S. Nat. Mus., No. 37,674.

This species is much like brunneum, from which it differs by its smaller, more delicate, and thinner shell, narrower and much shorter parietal lamina, its thinner and less reflected peristome, and its last whorl rising much less at its termination. From C. inflatum of Acklin Island, it differs especially by its striate last whorl, and more evenly fusiform shell not swollen toward the apex. This species was identified as inflatum by Mr. Maynard, as stated in Dr. Pilsbry's monograph of the genus, but a careful study of it shows that it cannot be so united." (Dall, 1905:441-442)

 

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