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The Atoll of Funafuti, Ellice group : its zoology, botany, ethnology and general structure based on collections made by Charles Hedley of the Australian Museum, Sydney, N.S.W.

Rlssoina Gemmea, Sp. nov. — (Fig. 11)

Rlssoina Gemmea, Sp. nov.
(Fig. 11).

Shell narrow, conical, white. Whorls eight (including two embryonic), rounded, suture lightly impressed. Embryonic whorls smooth, shining, apparently two, but a study of several species of the genus suggests that the topmost apparent whorl may contain several whorls wound in the same plane and concealed within the outermost. Sculpture—the last whorl is evenly and closely latticed by the intersection of eleven slender spiral cords, and about forty-two delicate longi-tudinal ribs; a smooth shining bead marks each crossing of the sculpture. The longitudinal ribs are slightly stronger than the spiral cords, a quarter of the breadth of their interstices, slightly oblique and curved; they cross regularly from base to suture and continue without stop-page at the suture, from whorl to whorl of the spire. Ascending the upper whorls, the spiral cords become fewer and gradually vanish leaving as vestiges a few denticles on the ribs. The spaces enclosed by themajorsculpture are square shallow pits, spirally striated. Round the base are wound three or four irregularly beaded cords.

Fig. 11.

Fig. 11.

Aperture oblique, produced in front, contracted anteriorly to a short spout; columella sharply recurved at the base, extending across the body-whorl as a thick layer of callus; posteriorly the lip is sharply folded at its junction with the body whorl. The outer lip is much thickened, grooved upon the inner face, denticu-late on the profile and with a heavy callus behind. Length 4, breadth 1½ mm.

One specimen in shallow water in the lagoon.

In this species the grains seem to be smaller and more numerous than in any other beaded Rissoina described.