Like oysters and mussels, clams are bivalves, a kind of mollusk that's encased in a shell made of two valves, or hinging parts. And that shell comes in all different sizes. There are small clams ...

Popular species of clam include: American hard shell clams – large clams with a thick, heavy shell Palourdes (also known as Manilla clams) – clams with a pretty, marbled shell that are ...