Clams feed upon plankton through a double-tubed siphon which operates like a snorkel. The siphon serves to obtain food and eliminate waste products. In-flowing water is pumped through the siphon, passed over the gills and strained to remove food particles. After oxygen is supplied and carbon dioxide received from the gills, water and waste products from the digestive tract are expelled through the outgoing siphon. Cherrystones are the popular New England clam bake size.
Littlenecks are the smallest, tenderest and most expensive.
They are usually served steamed with clam broth and garlic butter. Despite their sturdy appearance, clam shells are actually fragile and should be handled with care to avoid damage. Any clams with broken or gaping shells should be discarded. Live clams may be stored in the shell or shucked in the same manner as oysters. They also may be frozen in the shell for up to six months.