Gastropoda
Gastropoda , noun, plural
[New Latin, from Greek {not transcribed}, {not transcribed}, stomach + -poda.]
(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.
The Gastropoda are divided into three subclasses; namely: (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.