The ligament is internal and passes through a deep groove below the hinge in each valve, and has a broad plate beneath the hind lateral teeth.

The valves are finely sculptured with closely spaced concentric lines, and the annual growth rings are clearly visible.

It is found in the intertidal zone on rocky shores, lodged in crevices, in tufts of lichen or among the holdfasts ad fronds of seaweed, attached by byssus threads.

The veliger larval stage is omitted from the life cycle and when fully developed, juvenile molluscs are released and crawl away from the parent.

The majority of individuals inhabiting the same rock crevice are found to be clones of each other, having been developed parthenogenetically from a common ancestor.