Scallop is the common name for multiple species of bivalve mollusks that belong to the family Pectinidae. The most common varieties of scallop are the tiny bay scallop and the larger sea scallop, and they can be found in the shallow waters of every ocean near rocks, coral, rubble, sea grass, kelp, sand, or mud. Scallops have either convexly ridged or scalloped shells that hinge at one end. Only the adductor muscle that opens and closes the two shells is edible.