Mollusca

The molluscs (British spelling) or mollusks (American spelling) are members of the very large and diverse phylum of invertebrate animals known as Mollusca. There are some 112,000 species within this phylum. The scientific study of molluscs is known as malacology.

The word mollusc comes from the French mollusque, which originated from the Latin molluscus, meaning thin-shelled, from mollis, soft.

Molluscs range from minute snails and clams (micromollusks) to large organisms such as squid, cuttlefish and octopus, which are among the most neurologically-advanced invertebrates.

There are a wide variety of molluscs which are valued by humans as seafood or for their decorative shells. The edible species include many kinds of clams, snails, squid and octopuses.

The vast majority of molluscs live in marine environments, and many of them are found intertidally, in the shallow subtidal and on the continental shelf. Species of octopus and squid live throughout the ocean depths and some species of clam and limpet live in the abyssal depths of the oceans around hot vents.

Not all molluscs are marine: two taxonomic groups or classes, the bivalves and the gastropods, also contain freshwater species. Only the gastropods have representatives that live on land: the land snails and slugs.