Also called Beach Clams or Skimmer Clams, these oval, triangular bivalves are common with thinner shells than other clams. These shells are usually less than four inches in length but can grow up to eight inches. The umbo is central and not pushed to one side. They are tan to brown on the smooth outside with fine concentric growth lines and are lighter on the inside with a faint, white chalky area where the mantle once attached. Living buried beneath the sediment, they extend short siphons above the sediment to bring in water, which food and oxygen are extracted from, and to expel wastes. Large clams are dredged from the bottom by boat, as they are an important food source, which are often cooked and eaten as clam strips. 70% of clams taken commercially in the U.S. are Surfclams.