Orders: Decapoda (Sub-orders: Brachyura, Macrura), Schizopoda (including Anaspides), Stomatopoda, Sympoda (Cumacea), Isopoda (including Tanaidacea), Amphipoda.
There are at least seven orders: the stalk-eyed Brachyura, Macrura, Schizopoda, Stomatopoda, and the sessile-eyed Sympoda, Isopoda, Amphipoda.
Sympoda (or Cumaceans), in spite of their sessile eyes, have closer affinities with the stalk-eyed orders.
The more recent name Sympoda (see Willey, Results, pt.
In this genus alone of the known Sympoda the eyes sometimes form a pair, in accordance with the custom of all other malacostracan orders except this and of this order itself in the embryo (Sars, 1900).