(phylum Mollusca, class Bivalvia)
An order of bivalves whose shell has an homogeneous calcium carbonate microstructure. They are anisomyarian, with a greatly reduced anterior adductor muscle. The hinge is edentulous, and the gills protobranchiate. The valves are gaping, with the posterior end shorter than the anterior. The order first appeared in the Devonian. There is only one extant genus, Solemya.
Subjects: Zoology and Animal Sciences.