Bivalves

thumb|alt=Shell of the giant clam (Tridacna gigas)|Empty shell of the giant clam (Tridacna gigas) thumb|alt=Sword razor|Empty shells of the Ensis ensis|sword razor (Ensis ensis) Bivalvia () or bivalves, in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of aquatic molluscs (marine and freshwater) that have laterally compressed soft bodies enclosed by a calcified exoskeleton consisting of a hinged pair of half-shells known as valves. As a group, bivalves have no head and lack some typical molluscan organs such as the radula and the odontophore. Their gills hav

Cardiida is an order of bivalves belonging to the class Bivalvia.

Galeommatoidea is a superfamily of bivalves classified in the monotypic order Galeommatida.

Sphaeriida is an order of bivalves belonging to the class Bivalvia.