Cockle is the common name for a group of (mostly) small, edible, saltwater clams, marine bivalve molluscs in the family Cardiidae. Various species of cockles live in sandy, sheltered beaches throughout the world. The distinctive rounded shells of cockles are bilaterally symmetrical, and are heart-shaped when viewed from the end. Numerous radial ribs occur in most but not all genera. For an exception, see the genus Laevicardium, the egg cockles, which have very smooth shells.