The Mollusca, common name molluscs or mollusks, are a large phylum of invertebrate animals. There are around 85,000 recognized extant species of molluscs. Mollusca is the largest marine phylum, comprising about 23% of all the named marine organisms. Numerous molluscs also live in freshwater and terrestrial habitats. Molluscs are highly diverse, not only in size and in anatomical structure, but also in behaviour and in habitat.