Freshwater limpets

Key to genera | List of genera

Limpets, with their many shapes, sizes and colors, are a familiar sight on rocky marine shores, and it is difficult to mistake them for anything else. They are also common in fresh waters, although freshwater limpets are not as showy or diverse. Limpets are very closely related to snails, and are in fact snails whose shells do not coil.

The limpet genus Ferrissia (family Ancylidae) is common throughout the Northwest. It is relatively tolerant of human disturbance, particularly sedimentation. Ferrissia usually lives in the lotic waters of streams and rivers, but can sometimes be found in wetlands. The family Lymnaeidae, which includes the genera Lanx and Fisherola, has a very limited distribution relative to Ferrissia, and do not normally inhabit wetlands. Ferrissia is usually quite small and plain with a delicate shell, while Lanx and Fisherola have thicker, larger, and often more patterned shells.

An informative website about freshwater molluscs can be found at: http://members.aol.com/mkohl2/Fwlimpets.html