The opercula of multivalve shells are composed of two or four pieces, which are called the opercular valves.
multivalve, mul′ti-valv, n. a mollusc having a shell of more than two valves.
They are protected by a multivalve shell, and have long ciliated curled tentacles, whence their name (curl-footed).
An order consisting of molluscs which have multivalve shells, supported on a peduncle.
The sub-type in De Blainville's system, comprehending those with multivalve shells.