Myida
Myida 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.
Description
They are burrowing molluscs with well-developed siphons. The shell is relatively soft and lacks a nacreous layer. Some species have a single cardinal tooth.Superfamilies and families
Superfamilies and families within the Myida include :- Superfamily: Dreissenoidea
- * Family: Dreissenidae
- Superfamily: Myoidea
- * Family: Corbulidae
- * Family: Myidae
- * Family: †Pleurodesmatidae
- * Family: †Raetomyidae
- Superfamily: Pholadoidea
- * Family: Pholadidae
- * Family: Teredinidae
- * Family: Xylophagaidae
- Superfamily: †Pleuromyoidea
- * Family: †Ceratomyidae
- * Family: †Pleuromyidae
- * Family: †Vacunellidae