A few stomach-foots are found on land. It also has very hard teeth that are also used to scrape algae of rocks. Chitons are very, very slow moving. They include Clams, mussels, oysters and scallops. Most bivalves do not have radula because they eat by filtering water through their gills to obtain organic particles.
Most bivalves attach themselves to something or burrow underground.
Some scallops, however, do not attach themselves to anything and are able to swim by squirting water through their mantle. When an irritant, such as a grain of sand, becomes embedded in the mantle of a bivalve, the creatures coats the irritant with the same material used to produce the lining of its shell. This makes the irritant smooth and less painful to bivalve. The feet, or arms, of these creatures are connected to their heads, not their bodies. The rest of the body is in front of the head.