Identifying common slugs - Testacella species | The Conchological Society of Great Britain and Ireland

Garden molluscs | Slug or snail? | Testacella species

Most European slugs do not have an external shell. The exception is the genus Testacella, three species of which occur in Britain. The most common of these is T. scutulum.

All three species are subterranean, where they prey on earthworms and on other slugs. They usually occur in well manured ground in gardens and parks.

Testacella scutulum

Testacella scutulum Description: Large slug, extended length 8 - 12 cm. Yellow, speckled with black or brown, foot fringe and sole usually orange. Lateral grooves (which do not show up well in this illustration) join before reaching a common origin at the front edge of the mantle, just under the shell.

Testacella haliotidea Description: Large slug, extended length 8 - 12 cm. Usually dull creamy-white or yellow above, usually with a whitish foot-sole. Points of origin of lateral grooves at the front edge of the mantle (which are more obvious in this illustration) close together, but distinct.

Testacella maugei
Description: Medium to large slug, extended length 6 - 10 cm. Brown, speckled with black above, with a double row of conspicuous tubercles, and paler sides.Foot fringe and sole brighter, often pink or orange. Points of origin of lateral grooves about 5 mm. apart at the mantle. Shell larger than the other species, oblong and convex. 12 - 16 mm. long, 6 - 7 mm. wide. There are a number of colour varieties - grey, greenish-brown, rufous and black.