malacostraca

WORDNET DICTIONARY

malacostraca(n = noun.animal) subclass malacostraca - largest subclass of Crustacea including most of the well-known marine, freshwater, and terrestrial crustaceans: crabs; lobsters; shrimps; sow bugs; beach flies;

is a member of class crustacea, crustacea

is a kind of class

malacostraca, prop. n. pl. [NL., from Gr. malako`s soft + shell of a testacean.].

A subclass of Crustacea, including Arthrostraca and Thoracostraca, or all those higher than the Entomostraca. [1913 Webster]