"Cerion marielinum dominicanum, new subspecies

(Plate 10, figs. 1-3)

     Description. - Shell extended, reaching 30 mm. (about 1¼ inches), cylindrical, rimately perforate and with well developed axial costae. Color a mottled white and brown with the white predominating. Nuclear whorls yellowish brown and nearly smooth. Whorls 10 to 10½ and slightly convex. Spire extended, the last four whorls nearly equal in size, the remaining early forming a moderately convex one, which is produced at an angle of 70° to 75°. Aperture subquadrate. Outer lip thickened, somewhat expanded and reflected. Parietal lip straight, thinly glazed and forming moderate ridge. Parietal tooth small and weakly developed. Columellar tooth very small and extending back but little over one-half whorl. Columella short and slightly thickened. Umbilicus rimately formed and small, covered in part by the reflected lip. Suture well defined but only moderately indented. Sculpture consisting of numerous axial costae which number 19 to 26 on the body whorl. Fine and somewhat irregular growth lines exist between the costae. No spiral sculpture present.

     Types. - Holotype, Museum of Comparative Zoölogy no. 181904 and paratypes, M. C. Z. no. 181905 and Museo Poey no. 12670, from the east side of Boca del Rio Dominica, about 10 kilometers west of Mariel, Cuba. Additional paratypes from the west side of the river. C. G. Aguayo, W. J. Clench, L. Howell and R. D. Turner collectors, June 1950.

    Remarks. - This subspecies was found to be exceedingly abun­dant on the east side of the river, at least for some 1000 to 1500 feet east of the river mouth. The same form existed on the west side of the river, for at least a distance of one kilometer, but here live examples were rare, less than 50 specimens being found.

            Variation in size and color is rather limited. From C. marie­linum Pilsbry (Pl. 10, figs. 4-6) this subspecies differs in having the brown color marks on both the costae and the inter-spaces. In marielinum the brownish coloration is limited almost enterely to the inter-spaces, the costae remaining white. In addition, marie­linum is a somewhat larger form and has more strongly developed costae." (Clench and Aguayo, 1951:69-70)