Lacuna parva

(da Costa, 1778)

Description (shell):
Shell small, globular, with three rapidly expanding whorls; sutures deep. Apparently smooth but with delicate ornamentation of fine spiral striae and growth lines. Last whorl occupies most of spire; aperture rounded in male; more ovate, with basal flare or spout, in female. Umbilicus as in Lacuna vincta ; umbilical groove with longitudinal ridges.

Up to 4 x 4 mm.

Red-brown or horn-coloured, often with rufous bands on last whorl and lilac tinge to apex.

On seaweeds, lower shore; occasionally higher, where it may occur on Fucus vesiculosus . Sublittorally to 40 m.

Distribution similar to that of Lacuna vincta but extending further south to Spanish coasts (Distr. L. parva).