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Show 264 MR. E. A. SMITH ON THE MOLLUSCA [May 6, reflexed and appressed over the umbilical region, and joined extremity of the outer lip by a thin callosity. Greatest diameter 23 millim., smallest 19, height 15. Hab. Wild Island. The bands on this interesting species are usually three in number, one just below the peripherv and two above it. In some specimens there is an additional one above, in others there are but two altogether, sometimes both above the middle, or again one of them being beneath ; in other examples there may be only a single line either above or below the centre; and, finally,others are altogether unhanded. It recalls to mind H. eddystonensis, Reeve, which differs in being umbilicated, more acute at the periphery, more conical in the spire, with a sharper apex. 3. HELIX (GEOTROCHUS) LABILLARDIEREI. (Plate XXII. figs. 3, 3 a.) Shell small, imperforate, somewhat trochoid, totally white, or with a broad suffused brownish band below the middle of the body-whorl, or entirely light pinkish brown, always tipped with dark brown at the apex. Whorls 5, rather rapidly enlarging, moderately convex, sculptured with fine lines of growth and microscopical spiral striae; last rather sharply keeled at the middle, scarcely descending in front, and a little convex beneath. Aperture small, oblique, coloured like the exterior. Peristome white, broadly expanded, very slightly reflexed, thickened within the basal edge by a pale pinkish ridge. Greatest diameter 15 millim., smallest 12-^-, height 10|. Hab. Wild Island. Two characters are quite constant in this species-the dark coloured apex, and the peculiar thickening within the basal margin of the aperture. H. helicinoides, Hombron and Jacquinot, is related to this species, but differs in wanting the above peculiarities. 4. HELIX (HEMIPLECTA) INFRASTRIATA. (Plate XXII. figs. 4, 4 a.) Shell thin, semitransparent, corneous, narrowly perforate, de-pressedly concavely conical. Whorls 6, slightly convex, slowly enlarging, margined above the suture with a thread-like keel, very slightly glossy, sculptured with fine lines of growth, and more or less with microscopic spiral striae ; spire somewhat elevated, with concave outlines ; last whorl acutely carinate at the middle, not descending in front, a little convex beneath, glossy, marked with lines of increment and fine concentric wavy striae. Aperture oblique, angularly lunate. Peristome thin, not expanded or reflexed. Columellar margin almost perpendicular, expanded and reflexed over the narrow perforation. Greatest diameter 15 millim., smallest 13, height 10^. Hab. Dentrecasteaux Island, Admiralty Group. This species bears some resemblance to H. eucharis, Deshayes (non Reeve), but has a more concave spire, is more sharply keeled, and somewhat differently sculptured. The single shell described |
