Isopleura \I`so*pleu"ra\, n. pl. [NL. See {Iso-}, and {Pleura}.] (Zo["o]l.) A subclass of Gastropoda, in which the body is symmetrical, the right and left sides being equal. Note: The intestine terminates at the posterior end of the body, and the gills and circulatory and reproductive organs are paired. It includes the chitons ({Polyplacophora}), together with {Neomenia} and {Ch[ae]toderma}, which are wormlike forms without a shell.