crustacean
crus.ta.cean \.kr*-'sta--sh*n\ n [deriv. of L crusta crust, shell] : any of a large class (Crustacea) of mostly aquatic arthropods having a c hitinous or calcareous and chitinous exoskeleton and including the lobsters, shrimps, crabs, wood lice, water fleas, and barnacles - crustacean aj