The families of British non-marine molluscs (slugs, snails and mussels)
Morphology. Mussels, enclosed by a hinged, bivalve shell.
Eyes absent (the animal with no head). Without a byssus.
The shell breadth 90–170 mm in its maximum dimension; 90–170 mm wide (and about half as long across the shell from the hinge). The shell oblong, with the margin opposite the hinge more or less straight or only slightly incurved. The shell opaque (and robust); dull black, the interior pearly white or pinkish. The shells dull black, the interior pearly white or pinkish.
General biology, ecology. Freshwater aquatic. Breathing via complex gills. Restricted to clean, cool, fast-flowing rivers and streams at higher elevations, on sandy, gravelly or pebbly substrates; burrowing into interstices in the substrate.
British representation. Margaritifera (1, Freshwater or Scottish Pearl Mussel).
Illustrations. • Margaritifera margaritifer, with other Bivalvia (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. http://delta-intkey.com’.