Scientific classification: The subphylum Crustacea is placed in the phylum Arthropoda. The major classes in the subphylum Crustacea are the Branchiopoda (fairy shrimps, brine shrimps), Ostracoda (mussel, or seed, shrimps), Copepoda (copepods), Cirripedia (barnacles), and Malacostraca (crabs, lobster
