Faeroe and Norway to W. Mediterranean, in some patchy distribution. Grazer in shallow subtidal and upper infralittoral grounds, even in somewhat brackish waters (e.g. Scotland, in Barnes & al., 1994). Original taxon: Rissoa opalina.
« Shell ovato-globose, thin, transparent, very smooth and glossy, of a brownish colour and prismatic lustre ; whorls 3, convex, the last exceeding in size 3/4ths of the spire ; suture distinct ; apex blunt and rounded ; aperture roundish oval, large ; outer lip of the peristome thin, and not reflected or margined ; inner lip rather straight and thickened, not detached from the pillar ; umbilicus forming a narrow groove behind it ; operculum horny, thin, concentrically striate, and having its nucleus on the side next the pillar-lip… » – J. G. Jeffreys: “Notices of British shells”, Annals and Magazine of Natural History ser.2, vol. II, London 1848, p.351.
« Shell ovato-globose, thin, transparent, very smooth and glossy, of a brownish colour and prismatic lustre ; whorls 3, convex, the last exceeding in size 3/4ths of the spire ; suture distinct ; apex blunt and rounded ; aperture roundish oval, large ; outer lip of the peristome thin, and not reflected or margined ; inner lip rather straight and thickened, not detached from the pillar ; umbilicus forming a narrow groove behind it ; operculum horny, thin, concentrically striate, and having its nucleus on the side next the pillar-lip… » – J. G. Jeffreys: “Notices of British shells”, Annals and Magazine of Natural History ser.2, vol. II, London 1848, p.351.
Plage de la Franqui, Leucate, Occitania, S. France. 1,2mm. Original pictures provided by S. Clanzig (FR).
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