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.
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.
Tridacna crocea, the boring clam, crocus clam, crocea clam or saffron-coloured clam, is a species of bivalve in the family Cardiidae. It is native to the Indo-Pacific region. It is occasionally found in the aquarium trade where it is often simply referred to as crocea.
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.
The common cockle is a species of edible saltwater clam, a marine bivalve mollusc in the family Cardiidae, the cockles. It is found in waters off Europe, from Iceland in the north, south into waters off western Africa as far south as Senegal. The ribbed oval shells can reach 6 centimetres (2.4 in) across and are white, yellowish or brown in colour. The common cockle is harvested commercially and eaten in much of its range.
The pod razor is a coastal bivalve of European waters. It is edible and has been fished commercially, especially in Portugal, Spain, Ireland and Scotland.
The dog cockle or European bittersweet is a species of marine clam, a coastal bivalve mollusc of European waters.
Lajonkairia lajonkairii is an edible species of saltwater clam in the family Veneridae, the Venus clams. Common names include Manila clam, Japanese littleneck clam, Japanese cockle, and Japanese carpet shell. In Japan, it is known as asari. In Korea, it is known as bajirak.
Leukoma staminea, commonly known as the Pacific littleneck clam, the littleneck clam, the rock cockle, the hardshell clam, the Tomales Bay cockle, the rock clam or the ribbed carpet shell, is a species of bivalve mollusc in the family Veneridae. This species of mollusc was exploited by early humans in North America; for example, the Chumash peoples of Central California harvested these clams in Morro Bay approximately 1,000 years ago, and the distinctive shells form middens near their settlements.
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.
Hysteroconcha dione or the elegant Venus clam, formerly known as Venus dione, is a species of bivalve mollusc in the family Veneridae, the Venus clams.
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.
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.
Pholad borings are tubular burrows in firm clay and soft rock that have been created by bivalve molluscs in the family Pholadidae. The common names of clams in this family are "pholads", "piddocks", and "angel wings"; the latter because their shells are white, elongated and tend to be shaped like a wing and have sculpture somewhat reminiscent of a wing.
Polydora glycymerica is a species of annelid worm in the family Spionidae, native to the northwestern Pacific Ocean, where it lives commensally in association with a bivalve mollusc, usually Glycymeris yessoensis but occasionally with another species of clam. The worm intercepts food particles being drawn into the mollusc by its feeding current.
Spisula subtruncata, the cut through shell, is a medium-sized marine clam, or bivalve mollusc, found in the Eastern Atlantic from Iceland to Morocco and into the Mediterranean Sea. Common and sometimes very numerous. Up to 2.5 centimetres (0.98 in) long, with a distinct triangular shape. This species of clam is found in sandy and silty bottom in the sublittoral zone, where it lives as a sediment-burrowing filter feeder.
