\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.