﻿ Untitled 1  Invertebrate Anatomy OnLine  Mercenaria mercenaria
with notes on Tapes japonicus ©   Copyright 2001 by  Richard Fox
Lander University     Mollusca P, Eumollusca, Conchifera,
Ganglioneura, Ancyropoda, Bivalvia C, Metabranchia sC,
Eulamellibranchia SO, Veneroida O, Veneroidea SF,
Corbiculidae F (Fig 12-125, 12-122)  Mollusca P
            The mantle cavity, with its gills, is lateral. The
calcareous portion of the shell is bivalve, with the valves
opening laterally and joined dorsally by a derivative of the
periostracum.  Bivalvia C              Bivalvia is a large,
successful, and derived taxon.   The body is laterally
compressed and enclosed in a bivalve shell.   The two valves are
hinged dorsally.   The the foot is large and adapted for digging
in the ancestral condition.   A crystalline style is usually
present but never is there a radula.   The mantle cavity is
lateral and in most bivalves the gills are large and function in
respiration and filter-feeding.   The head is reduced