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| The families of non-marine molluscs of Britain and Ireland (slugs, snails and mussels) |
Morphology. Slugs, with no external shell.
35–55 mm long when fully extended. With a small, totally internal, symmetrical shell. Relatively small, slender and almost worm-like when fully extended. Contracting protectively when molested, but not assuming the hemispherical or sub-globular form characteristic of Arionidae. The body pale translucent greyish-yellow, the keel, back and head darker bluish-grey, the sole pale yellow. The mucous colourless. The mantle anterior and large; shagreened, and exhibiting a large dorsal island, demarcated by a conspicuous groove. The animal with two pairs of tentacles (the anterior pair short). Eyes at the tips of the posterior tentacles. The respiratory pore towards the posterior right of the mantle. The tail dorsally sharply keeled, the keel reaching to the mantle.
General biology, ecology. Terrestrial. Lifestyle somewhat subterranean (the worm-like, extensible body adapting B. palens to life in shrinkage cracks, root holes and worm burrows). Associated with sub-surface crevices, in damp ground, in disturbed places such as gardens, old quarries and roadside verges, especially under lightly embedded stones or bricks.
Hermaphrodite.
Classification. Gastropoda; Pulmonata.
Representation in Britain and Ireland. Boettgerilla (1, “Worm slug”).
We advise against extracting comparative information from the descriptions. This is much more easily achieved using the DELTA data files or the interactive key, which allows access to the character list, illustrations, 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. See also Guidelines for using data taken from Web publications.
Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 2005 onwards. The families of non-marine molluscs of Britain and Ireland (slugs, snails and mussels). Version: 5th August 2019. delta-intkey.com’.