Myida

Myida (formerly Myoida) is an order of saltwater and freshwater clams, marine and freshwater bivalve molluscs in the subclass Heterodonta. The order includes such bivalves as soft-shell clams, geoducks and shipworms.

Xylophaga is a genus of bivalves in the family Pholadidae.

Spheniopsidae is a family of bivalves belonging to the order Myida.