The Oyster

The common name oyster is used for a number of different groups of bivalve mollusks, most of which live in marine habitats or brackish water. The shell consists of two usually highly calcified valves which surround a soft body. Gills filter plankton from the water, and strong adductor muscles are used to hold the shell closed. Some types of oysters are highly prized as food, both raw and cooked. Other types, such as pearl oysters, are not commonly eaten. (taken from the J. Orlin Grabbe intertidal zone.)