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Show 528 MR. G. F. A N G A S O N S H E L L S F R O M MADAGASCAR. [June 5, light purplish brown, becoming darker behind the lip, partially covered with a pale straw-coloured epidermis ; spire depressed, whorls 4, rapidly increasing, somewhat convex, the last very wide, swollen, bluntly keeled; with a slight depression above the keel; aperture nearly horizontal, transversely lunately ovate, margined within with a broad band of purplish black, interior pale lilac ; peristome thickened, expanded, and reflected, edged with white; margins approximating and joined by a callus. Diam. maj. 1 inch 8 lines, min. 1 inch 3| lines, alt. 9 lines. Hab. Ekongo, S.E. coast of Madagascar. This interesting shell may at once be distinguished from H. sepulchralis and its allies by its elaborate sculpture, and by the expanded form of the aperture. H E L I X EKONGENSIS, n. sp. (Plate LIV. fig. 4.) Shell minutely umbilicated, depressedly globose, very thin, the oblique lines of growth crossed by exceedingly fine, close-set, concentric lines, pale horn-colour, with one narrow brown band above the suture on the upper whorls, and two on the last whorl, one on either side of the periphery ; spine depressedly conical, apex obtuse ; whorls 6, flatly convex, the last not descending ; aperture oblique, lunately ovate ; outer thin, simple. Diam. maj. 11 lines, min. 10 lines, alt. 6 lines. Hab. Ekongo, S.E. Madagascar. H E L I X BALSTONI, n. sp. (Plate LIV. fig. 5.) Shell imperforate, depressedly conoidal, thin, sculptured all over with extremely fine, close-set, engraved lines that cross each other obliquely both ways, giving the surface a delicately shagreened appearance under the lens, fulvous horn-colour throughout; spire depressedly conical, apex somewhat obtuse ; whorls 6, flatly convex, the last sharply keeled at the periphery, not descending in front; base convex, shining; aperture oblique, quadrately ovate; outer lip thin, simple. Diam. maj. 1 inch 2 lines, min. 1 inch, alt. 7 lines. Hab. Interior of Madagascar. In form, this species greatly resembles Helix semidecussata, Pfr., from India ; but the sculpture of the whorls is quite different, and is remarkable for its extreme delicacy and beauty. At the request of Mr. Edward Bartlett I have named this shell after Mr. W . E. Balston. PHYSA MADAGASCARIENSIS, n. sp. (Plate LIV. figs. 2 a, 2 bi) Shell sinistral, perforate, thin, longitudinally plicately striated, the striae being more regular on the upper whorls, horn-coloured ; spire obtusely conical, apex blunt; whorls 4\, convex, the last large and inflated ; aperture ovate, narrower above ; outer lip thin, simple, arcuate; columella with a broad callus expanded over the umbilical region. Alt. 8 lines, diam. 5\ lines. Hab. Okongo, S.E. Madagascar. |