LIMPET, Patella, a genus of gasteropodous mollusks, of the order eyelobranchicstes, the type of the family patellidce. In all this family the shell is nearly conical, not spiral, and has a wide mouth, and the apex turned forwards. The animal has a large round or oval muscular foot, by which it adheres firmly to rocks, the power of creating a vacuum. being aided by a viscous secretion. Limpets live on rocky coasts, between tide-marks, and remain firmly fixed to one spot when the tide is out, as their gills cannot bear exposure to the air, but move about when the water covers them; many of them, how ever, it would seem, remaining long on the same spot, which in soft calcareous rocks is. found hollowed to their exact form. They feed on algm, which they eat by means of a. long ribbon-like tongue, covered with numerous rows of hard teeth; the Commox LIMPET' (P. vulgaris) of the British coasts having no fewer than 160 rows of teeth on its tongue, 12 in eaeli row-1920 teeth in all. The tougue, when not in use, lies folded deep in the
interior of the animal. The gills are arranged under the margin of the mantle, between it and the foot, forming a circle of leaflets. The sexes are distinct.—The power of adherence of limpets to the rock is very great, so that, unless surprised by sudden seizure, they are not easily removed without violence sufficient to break the shell. The species are numerous, and exhibit many varieties of form and color. The common limpet is, most abundant on the rocky coasts of Ifritain, and is much used for bait by fishermen; it is also used for food. Some of the limpets of warmer climates have very beautiful shells. A species found on the western coast of South. America has a shell a foot wide, which is often used as a basin.