The close species Rissoa violacea Desmarest, 1814. Top: a typical form with the dark spiral band. Bottom: a pale shell without the spiral pattern. R. lilacina can be confused with such unusual specimens. But R. violacea remains more slender, with a less marked longitudinal sculpture.

« Shell ovate, rather broad and thick, tapering to a pretty acute point, yellowish white or brown, more or less tinged with violet; with seven rather flat whorls; the upper ones smooth, two or three of the lower with about twelve strong ribs. The ribs are frequently only observable on the penultimate and a part of the last whorls, always disappearing before they reach the lip. The whole surface of the last whorl is covered with punctures formed by the crossing of obscure longitudinal and transverse lines. The spaces between the ribs are coarsely striated. Aperture roundish oval, slightly angulated above, generally of a violet or purplish brown colour, and having a very broad white rib behind it. Inner lip slightly reflected on the pillar, without umbilicus. » – op. cit. p.325.

Alder: « This species nearly resembles the R. violacea of Desmarest, but is shorter and thicker, and without the spiral band. I have adopted the manuscript name attached to specimens in the British Museum. The same species, unnamed, is also in the museum of the Jardin des Plantes at Paris. » – Specimens from Lanvéoc, Finistère, NW. Brittany, NW. France. Sizes circa 3,5-4mm. R  Huet legit (FR).