A seashell or sea shell, also known simply as a shell, is a hard, protective outer layer usually created by an animal that lives in the sea. The shell is part of the body of the animal. Empty seashells are often found washed up on beaches by beachcombers. The shells are empty because the animal has died and the soft parts have been eaten by another animal or have decomposed.
The gastropods, commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda.
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.
Scallop is a common name that is primarily applied to any one of numerous species of saltwater clams or marine bivalve mollusks in the taxonomic family Pectinidae, the scallops. However, the common name "scallop" is also sometimes applied to species in other closely related families within the superfamily Pectinoidea, which also includes the thorny oysters.
A siphon is an anatomical structure which is part of the body of aquatic molluscs in three classes: Gastropoda, Bivalvia and Cephalopoda.
The Pteriomorphia comprise a subclass of saltwater clams, marine bivalve molluscs. It contains several major orders, including the Arcida, Ostreida, Pectinida, Limida, Mytilida, and Pteriida. It also contains some extinct and probably basal families, such as the Evyanidae, Colpomyidae, Bakevelliidae, Cassianellidae, and Lithiotidae.
Mactridae, common name the trough shells or duck clams, is a family of saltwater clams, marine bivalve mollusks in the order Venerida.
The Pinnidae are a taxonomic family of large saltwater clams sometimes known as pen shells. They are marine bivalve molluscs in the order Pteriida.
Placunidae, also known as windowpane oysters, windowpane shells, and Capiz shells, are a taxonomic family of saltwater clams, marine bivalve mollusks which are related to oysters and scallops.
Isognomon is a genus of marine bivalve mollusks which is related to the pearl oysters.
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.
Acanthopleura granulata, common name the West Indian fuzzy chiton, is a medium-sized tropical species of chiton. This type of chiton’s activity does not depend on spring-neap oscillations leading to lower locomotion loss. Its morphology is different from usual chitons as it has a fifth valve, which is split into halves.
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.
Gregariella is a genus of mussels in the family Mytilidae.
Tellimya ferruginosa is a species of small marine bivalve mollusc in the family Lasaeidae. It is found on the eastern side of the Atlantic Ocean.
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.
Neotrigonia margaritacea, common name the pearly brooch-shell, is a species of saltwater clam, a marine bivalve mollusc in the family Trigoniidae. This species is known from sandy substrates in shallow seas in southeastern and southwestern Australia. This species was the first member of the family to be discovered alive; previous to its discovery, trigoniids were only known from fossils.
Ostreoidea is a taxonomic superfamily of bivalve marine mollusc, sometimes simply identified as oysters, containing two families. The ostreoids are characterized in part by the presence of a well developed axial rod. Anal flaps are known to exist within the family Ostreidae but not within the more-primitive Gryphaeidae. The scar from the adductor muscle is simple, with a single, central scar. In the majority, the right valve is less convex than the left.
Eurytellina simulans is a species of bivalve mollusc. This species was previously known as Tellina simulans. The animal was originally described to science by naturalist Charles Baker Adams, a professor of zoology at Amherst College. Adams left for an expedition to Panama in mid-November 1850. He collected furiously upon arrival and on January 3, 1851 shipped eight crates back to Massachusetts. These contained 41,830 specimens of 516 species of molluscs. He described Tellina simulans on the basis of a single valve.
Tawera spissa, the morning star shell, is a species of marine bivalve from the Veneridae family. T. spissa is endemic to New Zealand.
