A subclass of Gastropoda, in which the body is symmetrical, the right and left sides being equal. [
1913 Webster]
" 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 Chætoderma, which are wormlike forms without a shell."
[1913 Webster]