Cilia on palps sweep food into the mouth. Non-burrowing bivalves are all filter feeders, but burrowers can be either filter or deposit feeders. Their 'arteries' lead from the heart to the foot. A valve in the vein is closed. The foot is thrust forward, the end of the foot swells and serves as an anchor.
Longitudinal muscles constract and the shell is pulled forward.
They rapidly open and close their valves, squirting water in a directed fashion. This is a less permanent attachment than cementation. The byssus is generally present in juveniles of most species to stabilize the shell. The most vagile animals are bilaterally symmetrical. Gills are housed in the posterior half of the shell.