Gastropods are a type of mollusc. Molluscs comprise a large and diverse phylum of nearly 90,000 extant species that includes cephalopods (e.g., squid, octopus), gastropods (e.g. snails and slugs), and bivalves (e.g., clams, oysters and scallops). Gastropods comprise the majority (ca. 60,000+ species) of Mollusca. Below are gastropods common in the plankton assemblages of Mid-Atlantic coastal waters.