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. The shipworms bore into wood, clay, or stone and live inside these substances.
The Pacific razor clam, Siliqua patula, is a species of large marine bivalve mollusc in the family Pharidae.
Tresus capax is a species of saltwater clam, marine bivalve mollusk, common name the fat gaper, in the family Mactridae. It also shares the common name horse clam with Tresus nuttallii a species which is similar in morphology and lifestyle. Both species are somewhat similar to the geoduck, though smaller, with shells up to eight inches long (20 cm), weight to 3–4 lb (1.4–1.8 kg).
Hippopus hippopus, also known as the Horse Hoof clam and Strawberry clam, is a species of giant clam in the Family Tridacna and the genus Hippopus. Hippopus is a delicacy in many Southeast Asian countries due to its high quality meat.
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.
Macoma nasuta, commonly known as the bent-nosed clam, is a species of bivalve found along the Pacific Ocean coast of North America. It is about 6 cm (2.4 in) long. It is often found buried in sands of 10–20 cm (3.9–7.9 in) in depth. This rounded clam has no radial ribs. Archaeological data supports the use of this species by Native Americans such as the Chumash peoples of central California.
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.
Arca zebra, or the turkey wing ark clam, is a bivalve mollusc in the family Arcidae, the ark clams.
Codakia orbicularis, or the tiger lucine, is a species of bivalve mollusc in the family Lucinidae. It can be found along the Atlantic coast of North America, ranging from Florida to the West Indies.
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.
Lutraria is a genus of medium-sized marine bivalve mollusks or clams, commonly known as otter shells.
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.
Mulinia lateralis, the dwarf surf clam or coot clam, is a species of small saltwater clam, a bivalve mollusc in the family Mactridae. It occurs in the western Atlantic Ocean and the Caribbean Sea.
Tresus nuttallii, common name the Pacific gaper, is a species of saltwater clam, a marine bivalve mollusk in the family Mactridae. It also shares the common name horse clam with Tresus capax, a species which is similar in morphology and lifestyle. Both species are somewhat similar to the Geoduck, though smaller, with shells up to eight inches long (20 cm), weight to 3–4 lb (1.4–1.8 kg).
Calyptogena magnifica is a species of giant white clam found clustered around hydrothermal vents at abyssal depths in the Pacific Ocean.
Sanguinolaria is a genus of saltwater clams, marine bivalve molluscs of the family Psammobiidae.
Saxidomus gigantea is a large, edible saltwater clam, a marine bivalve mollusk in the family Veneridae, the venus clams. It can be found along the western coast of North America, ranging from the Aleutian Islands to San Francisco Bay. Common names for this clam include butter clam, Washington clam, smooth Washington clam and money shell.
Nuttallia is a genus of saltwater clams, marine bivalve molluscs in the family Psammobiidae.
Potamocorbula amurensis is a species of small saltwater clam, a marine bivalve mollusc in the order Myida. Common names include the overbite clam, the Asian clam, the Amur River clam and the brackish-water corbula. The species is native to marine and brackish waters in the northern Pacific Ocean, its range extending from Siberia to China, Korea and Japan. It has become naturalised in San Francisco Bay.
