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 two pairs of tentacles. Eyes at the tips of the posterior tentacles.

The shell inoperculate; rising-spiral; 6.5–8 whorled; typically dextral; 8.5–9 mm in its maximum dimension; higher than wide; 8.5–9 mm high (E. obscura), or 14–17 mm high (E. montana); 3.7 mm wide (E. oscura), or 6.7 mm wide (E. montana); height about 2.32–2.33 x the width; high-spired and tapered gradually from the body whorl. The height of the spire about 0.49–0.52 x that of the shell. The spire acute to obtuse. The shell tear-shaped; fairly shallowly sutured. The body whorl moderately convex. The whorls of the spire feebly convex to moderately convex. The whorls neither shouldered nor keeled. The shell not markedly striated across the whorls (sculptured only with fine growth lines and/or striae). The aperture with neither teeth nor calluses. The columella folded. The shell with an umbilicus. The umbilicus small (and deep). The shell thick-lipped; thin and translucent to opaque; light brown or transparent horn-coloured, not very glossy; plain.

General biology, ecology. Terrestrial. In ground litter in woods, hedgerows, etc., mainly on base-rich soils, often climbing up tree trunks or walls in wet weather.


Classification. Gastropoda; Pulmonata.

British representation. Ena (2, “Bulin snails”).

Illustrations. • Ena montana and Ena obscura, with Clausiliidae, Chondrinidae, Cochlicopidae, Ferussaciidae and Pupillidae (Ellis). • Ena montana and E. obscura, with Chondrinidae, Pupillidae, Vertiginidae (Adams).

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.’.