(Science: zoology) 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.
alternative forms: 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.