a

Gastropoda Gas*trop"o*da, n. pl., [NL., fr. Gr. ?, ?, stomach + -poda.] (Zo["o]l.) 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}.] [1913 Webster]

Note: 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. [1913 Webster]