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. Bivalves as a group have no head and they lack some usual molluscan organs like the radula and the odontophore. They include 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.
A siphon is an anatomical structure which is part of the body of aquatic molluscs in three classes: Gastropoda, Bivalvia and Cephalopoda.
The word lunula means little moon and may also refer to:
In anatomy, an apex is part of the shell of a mollusk. The apex is the pointed tip of the shell of a gastropod, scaphopod, or cephalopod.
The aperture is an opening in certain kinds of mollusc shells: it is the main opening of the shell, where the head-foot part of the body of the animal emerges for locomotion, feeding, etc.
Lirae are fine lines or ridges that are a sculptural feature of the outside of the shells of various animals. The term is commonly applied to the shells of molluscs such as gastropods, bivalves and nautiloids. It can also be used to describe similar sculpture on the surface of the shells of brachiopods.
Venus is a genus of small to large saltwater clams in the family Veneridae, which is sometimes known as the Venus clams and their relatives. These are marine bivalve molluscs.
A protoconch is an embryonic or larval shell which occurs in some classes of molluscs, e.g., the initial chamber of an ammonite or the larval shell of a gastropod. In older texts it is also called "nucleus". The protoconch may sometimes consist of several whorls, but when this is the case, the whorls show no growth lines.
Mytilida is an order of marine bivalve molluscs, commonly known as true mussels. There is one extant superfamily, the Mytiloidea, with a single extant family, the Mytilidae.
A mollusc valve is each articulating part of the shell of a mollusc. Each part is known as a valve or in the case of chitons, a "plate". Members of two classes of molluscs: the Bivalvia (clams) and the Polyplacophora (chitons) have valves.
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.
Half-moon cookies are Filipino semicircle or crescent-shaped butter cookies. It has a soft crumbly texture and a sweet flavor with a salty aftertaste.
The grooved carpet shell, or Palourde clam, Ruditapes decussatus, or Venerupis decussatus, is a clam or bivalve mollusc in the family Veneridae. It is distributed worldwide and due to its ecological and economic interest has been proposed as a bioindicator.
Chamelea gallina is a species of small saltwater clam, a marine bivalve in the family Veneridae, the venus clams.
Juliidae, common name the bivalved gastropods, is a family of minute sea snails, marine gastropod mollusks or micromollusks in the superfamily Oxynooidea, an opisthobranch group. These are sacoglossan (sap-sucking) sea snails, and many of them are green in color.
A callus is an anatomical feature that exists in some mollusk shells, a thickened area of shell material that can partly or completely cover the umbilicus, or can be located as a coating on the body whorl near the aperture of the shell.
The umbo is the vaguely defined, often most prominent, highest part of each valve of the shell of a bivalve or univalve mollusk. It usually contains the valve's beak, the oldest point of the valve, and its degree of prominence and its position relative to the hinge line are sometimes helpful in distinguishing bivalve taxa. The umbo forms while the animal is a juvenile, and radial growth subsequently proceeds around that area. The umbo is situated above the hinge line. In those bivalves where the umbones do not protrude, as is the case for example in some mussels, the umbones can nonetheless usually be readily identified by examining the concentric growth lines of the shell.
A hinge ligament is a crucial part of the anatomical structure of a bivalve shell, i.e. the shell of a bivalve mollusk. The shell of a bivalve has two valves and these are joined together by the ligament at the dorsal edge of the shell. The ligament is made of a strong, flexible and elastic, fibrous, proteinaceous material which is usually pale brown, dark brown or black in color.
