Orders: Decapoda (Sub-orders: Brachyura, Macrura), Schizopoda (including Anaspides), Stomatopoda, Sympoda (Cumacea), Isopoda (including Tanaidacea), Amphipoda.
A comparison with the related Tanaidacea (fig.
In the Decapoda three pairs are thus modified, and in the Tanaidacea, Isopoda and Amphipoda only one.
In the Cumacea and Tanaidacea only the first thoracic limb has a branchial epipodite.
Among the Malacostraca some Schizopoda, the Cumacea, Tanaidacea, Isopoda and Amphipoda (sometimes grouped all together as Peracarida) have a marsupium or brood-pouch formed by overlapping plates attached to the bases of some of the thoracic legs.