Malacostraca Malacosoma • malacostracan · · · Info · Definitions · Characters · · Malacostraca · · Text Latin · · Script 12 · · Length Definitions · · · (noun) largest subclass of Crustacea including most of the well-known marine, freshwater, and terrestrial crustaceans: crabs; lobsters; shrimps; sow bugs; beach flies. Synonyms: subclass Malacostraca. · · Noun Definition 1 Characters · · M latin capital letter m U+004D a latin small letter a U+0061 c latin small letter c U+0063 l latin small letter l U+006C o latin small letter o U+006F r latin small letter r U+0072 s latin small letter s U+0073 t latin small letter t U+0074