| Noun | 1. | subclass Malacostraca - largest subclass of Crustacea including most of the well-known marine, freshwater, and terrestrial crustaceans: crabs; lobsters; shrimps; sow bugs; beach fliesclass Crustacea, Crustacea - class of mandibulate arthropods including: lobsters; crabs; shrimps; woodlice; barnacles; decapods; water fleas malacostracan crustacean - a major subclass of crustaceans Decapoda, order Decapoda - lobsters; crayfish; crabs; shrimps; prawns Euphausiacea, order Euphausiacea - small commonly luminescent crustaceans; important element of marine plankton: krill Mysidacea, order Mysidacea - opossum shrimp Isopoda, order Isopoda - woodlice Amphipoda, order Amphipoda - small flat-bodied semiterrestrial crustaceans: whale lice; sand-hoppers; skeleton shrimp class - (biology) a taxonomic group containing one or more orders |