Mercuria confusa

(Frauenfeld, 1863)

Shell is small, semitransparent, glossy, with a blunt tip. There are 5-6 tumid whorls forming a rather broad, squat shell with a apical angle of about 66°, this is much greater than that of species of Hydrobia and Potamopyrgus . There is a well marked umbilicus. The last whorl occupies about three quarters of the shell height, the aperture about half.

Up to 4 x 2 mm.

Pale horn colour.

The tentacles are long and pale except for a central longitudinal brown band.

In brackish, nearly fresh water, mainly in the upper tidal reaches of quiet-running rivers.

Wide-spread in Iberia and France, rare in the British Isles. Records also from Belgium and the Netherlands (Distr. M. confusa).