- Lamellibranch - Type of mollusc - A mollusk having a shell consisting of two lateral plates
or valves joined together by an elastic ligament at the hinge, which is
usually strengthened by prominences called teeth. The shell is closed
by the contraction of two transverse muscles attached to the inner
surface, as in the clam, -- or by one, as in the oyster. See Mollusca. - A pericarp in which the seed case opens or splits into two
parts or valves. - Having two shells or valves which open and shut, as the
oyster and certain seed vessels.