The Lutrariidae are large lamellibranchs which burrow deeply in bottom-deposits on the shore and in shallow water. The foot is relatively weak, and they live permanently buried 30 cm or so beneath the surface, maintaining connexion with the overlying water through their long siphons, which are united in a common sheath for practically their whole length. The commonest British species, Lutraria lutraria (L.) is found at low-water mark on shores of muddy sand, and offshore its siphons are sometimes taken by the dredge or grab. Another species, L. magna (da Costa) is more local, and appears to inhabit muddy deposits near the mouths of estuaries. It is a southern form, being occasionally found on the south and west coasts of the British Isles, and, like L. lutraria, its range extends southward to the Mediterranean.