(mol'-lusc) A solitary invertebrate belonging to the phylum Mollusca, characterized by a nonsegmented body that is bilaterally symmetrical, and by a radially or biradially symmetrical mantle and shell. Among the classes included in the molluscs are the gastropods (snails), bivalves (pelecypods), and cephalopods (squid, nautiluses, ammonites, and octopi).
n. Any soft-bodied invertebrate of the phylum Mollusca, usually wholly or partly enclosed in a calcium-carbonate shell secreted by a soft mantle covering the body, and often possessing a single foot and a radula.
common name for members of a phylum (sub-section of the animal kingdom) of soft-bodied animals, with bodies usually covered by a hard external shell. Some molluscs, like the octopus, do not possess a shell.
phylum of invertebrates which include modern creatures such as snails, slugs, cockles, and squids. Molluscs have a muscular 'foot' for digging, movement, or swimming. Many have a hard protective shell. Some forms such as most slugs and octopuses have lost their shells as they have developed other ways of protecting themselves. Molluscs are common fossils found in rocks from the Cambrian period onwards, and are especially common in the Mesozoic and Cenozoic. (See Geological Timescale).
An aquatic, soft-bodies invertebrate that lives in a shell, found either in seawater or freshwater. If it has only one shell (e.g. the abalone shell), it is “univalve”. If it has two shells connected by a hinge, it is an oyster or “bivalve” mollusc.