Definition:
A mollusk is an animal classified in the Phylum Mollusca.
This extremely diverse animal phylum is thought to contain well over 100,000 species, which include animals in the taxonomic classes Polyplacophora (chitons), Gastropoda (animals with one shell, including snails, limpets, and sea slugs/nudibranchs), Bivalvia (animals with two shells - clams, mussels and oysters) and Cephalopoda (octopuses and squids).
