The families of British non-marine molluscs (slugs, snails and mussels)


L. Watson and M. J. Dallwitz


Morphology. Snails, with a conspicuous, spiral, univalve shell.

The animal with one pair of tentacles only. Eyes at the tips of the posterior tentacles (i.e., on the only pair).

The shell inoperculate; rising-spiral; 4.5–6.5 whorled; typically sinistral (some Vertigo spp.), or dextral; 1.7–3.5(–4) mm in its maximum dimension; higher than wide; 1.7–3.5(–4) mm high; 0.9–1.5 mm wide; height about 1.5–2.05 x the width; high-spired and tapered gradually from the body whorl. The height of the spire about 0.38–0.58 x that of the shell. The spire obtuse. The shell cylindrical, or ovoid-symmetric; deeply sutured. The body whorl only slightly convex to very strongly convex. The whorls of the spire feebly convex to very strongly convex. The whorls neither shouldered nor keeled. The shell conspicuously and regularly striated across the whorls to not markedly striated across the whorls. The aperture bearing teeth (Vertigo), or bearing calluses (Columella, Truncatellina). The columella folded. The shell with an umbilicus (small), or without an umbilicus. The umbilicus when present, small. The shell thin-lipped (though the the mouth edge is sometimes slightly expanded); thin and translucent, or thin and translucent to opaque; pale to dark brown or horn-coloured, dull or glossy; plain.

General biology, ecology. Terrestrial. In a diversity of wet or dry habitats.


Classification. Gastropoda; Pulmonata.

British representation. “Chrysalis snails, Whorl snails”: Columella (3), Truncatellina (2), Vertigo (11).

Illustrations. • Columella, Vertigo, Truncatellina, with Chondrinidae, Enidae and Pupillidae (Adams). • Vertigo substriata: living animal (Reeve).

To view the illustrations with detailed captions, go to the interactive key. This also offers full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, and distributions of character states within any set of taxa.

Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 2005 onwards. The families of British non-marine molluscs (slugs, snails and mussels). Version: 4th January 2012.’.