GASTROPODA

‖Gas‐trop″o‐da (?), n. pl., [[NL., fr. Gr. �, �, stomach + -poda.]] (Zoöl.) One of the classes of Mollusca, of great extent. It includes most of the marine spiral shells, and the land and fresh-water snails. They generally creep by means of a flat, muscular disk, or foot, on the ventral side of the body. The head usually bears one or two pairs of tentacles. See Mollusca. [Written also Gasteropoda.] ☞ The Gastropoda are divided into three subclasses; viz.: (a) The Streptoneura or Dioecia, including the Pectinibranchiata, Rhipidoglossa, Docoglossa, and Heteropoda. (b) The Euthyneura, including the Pulmonata and Opisthobranchia. (c) The Amphineura, including the Polyplacophora and Aplacophora.