Clam is a common name for several kinds of bivalve molluscs. The word is often applied only to those that are edible and live as infauna, spending most of their lives halfway buried in the sand of the seafloor or riverbeds. Clams have two shells of equal size connected by two adductor muscles and have a powerful burrowing foot. They live in both freshwater and marine environments; in salt water they prefer to burrow down into the mud and the turbidity of the water required varies with species and location; the greatest diversity of these is in North America.
Bivalvia, in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of marine and freshwater molluscs that have laterally compressed bodies enclosed by a shell consisting of two hinged parts. As a group, bivalves have no head and they lack some usual molluscan organs, like the radula and the odontophore. The class includes the clams, oysters, cockles, mussels, scallops, and numerous other families that live in saltwater, as well as a number of families that live in freshwater. The majority are filter feeders. The gills have evolved into ctenidia, specialised organs for feeding and breathing. Most bivalves bury themselves in sediment, where they are relatively safe from predation. Others lie on the sea floor or attach themselves to rocks or other hard surfaces. Some bivalves, such as the scallops and file shells, can swim. Shipworms bore into wood, clay, or stone and live inside these substances.
A siphon is an anatomical structure which is part of the body of aquatic molluscs in three classes: Gastropoda, Bivalvia and Cephalopoda.
Pholadidae, known as piddocks or angelwings, are a family of bivalve molluscs similar to a clam.
Teredo navalis, commonly called the naval shipworm or turu, is a species of saltwater clam, a marine bivalve mollusc in the family Teredinidae. This species is the type species of the genus Teredo. Like other species in this family, this bivalve is called a shipworm because it resembles a worm in general appearance while at the anterior end it has a small shell with two valves, and it is adept at boring through wood.
The razor shell, Ensis magnus, also called razor clam, razor fish or spoot (colloquially), is a bivalve of the family Pharidae. It is found on sandy beaches in Canada and northern Europe.
A bivalve shell is part of the body, the exoskeleton or shell, of a bivalve mollusk. In life, the shell of this class of mollusks is composed of two hinged parts or valves. Bivalves are very common in essentially all aquatic locales, including saltwater, brackish water, and freshwater. The shells of bivalves commonly wash up on beaches and along the edges of lakes, rivers, and streams. Bivalves by definition possess two shells or valves, a "right valve" and a "left valve", that are joined by a ligament. The two valves usually articulate with one another using structures known as "teeth" which are situated along the hinge line. In many bivalve shells, the two valves are symmetrical along the hinge line—when truly symmetrical, such an animal is said to be equivalved; if the valves vary from each other in size or shape, inequivalved. If symmetrical front-to-back, the valves are said to be equilateral, and are otherwise considered inequilateral.
Mya truncata, common name the blunt gaper or truncate softshell, is a species of edible saltwater clam, a marine bivalve mollusk in the family Myidae.
Ensis ensis, or the sword razor, is a razor clam, a marine bivalve mollusc in the family Pharidae. It lives buried in the sand and is found off the coasts of northwest Europe.
Fabulina fabula, the bean-like tellin, is a species of marine bivalve mollusc in the family Tellinidae. It is found off the coasts of northwest Europe, where it lives buried in sandy sediments.
Tellina tenuis, the thin tellin, is a species of marine bivalve mollusc in the family Tellinidae. It is found off the coasts of northwest Europe and in the Mediterranean Sea, where it lives buried in sandy sediments.
Abra alba, or the white furrow shell, is a species of bivalve mollusc in the family Semelidae. It occurs in the northeastern Atlantic Ocean and the Mediterranean Sea, where it lives on the floor in shallow areas buried in soft sediments.
Phaxas pellucidus, the transparent razor shell, is a species of marine bivalve mollusc in the family Pharidae. It is found buried in the seabed in coastal waters of northwest Europe, often in great numbers.
Lutraria is a genus of medium-sized marine bivalve mollusks or clams, commonly known as otter shells.
Lutraria lutraria is a species of large marine bivalve mollusc in the family Mactridae. Its common names include the otter shell and the common otter shell. It occurs in coastal regions of the north east Atlantic Ocean where it lives buried in the sand.
Corculum cardissa, the heart cockle, is a species of marine bivalve mollusc in the family Cardiidae. It is found in the Indo-Pacific region. It has a symbiotic relationship with dinoflagellates (zooxanthellae), which live within its tissues.
Cyrtopleura costata, or the angel wing clam, is a bivalve mollusc in the family Pholadidae. It is found in shallow parts of the northwest Atlantic and also in the North Sea of Scotland coastline and west coast of the Adriatic Sea by a remote area in the Marche region in central Italy, living in the seabed, where it digs its burrows on a very slow revolving movement for years through soft sand and mud always to a max depth of 8ft but always below 3 feet (0.91 m) at the lowest tide.
Donax vittatus, or the banded wedge shell, is a species of bivalve mollusc in the order Cardiida. It is found on beaches in northwest Europe buried in the sand on the lower shore.
Macoma tenta, the narrowed macoma clam or elongate macoma is a species of clam, a marine bivalve mollusk (bivalvia) in the family Tellinidae and genus Macoma. Macoma tenta are one of two species of macoma clams that can be found in the Chesapeake Bay on the eastern shore of the United States in Maryland and Virginia. The macoma tenta like their cousin in the Chesapeake, the Macoma balthica or Baltic macoma clam, are small marine bivalves with thin, chalky white shells. They tend to live buried in the sandy or muddy areas of shallow water in the middle and lower Chesapeake Bay. Macoma clams are among the most abundant clams in the Chesapeake Bay. Macomas first appeared about 750,000 years ago.
Pharus legumen, is a species of bivalve mollusc commonly found burrowed in the sand on lower shores and in the shallow sublittoral.
