Molluscs

Snails, clams, octopuses, and other familiar forms are members of the phylum Mollusca. Molluscs have been very successful: there are more species of molluscs in the ocean than any other animal group. There may be as many as 200,000 species of molluscs, which are surpassed only by the arthropods as the largest phylum of animals.
Most molluscs have:

• A mantle-covered body.
• A ventral, muscular foot, usually used in locomotion.
• A radula, a ribbon of small teeth that is used to feed, usually by rasping food from surfaces.