the larger divisions of Crustacea, so-called since the thorax and stomach are both segmented; Tetradecapoda. It offers the Amphipoda and Isopoda.
In Gegenbaur's system of classification, one of two prime divisions of malacostracous crustaceans (one other being Thoracostraca), matching around towards the edriophthalmous or sessile-eyed crustaceans of other writers, and split into the 3 purchases Amphipoda, Læmodipoda, and Isopoda.
In Burmeister's system of classification, certainly one of three orders of Crustacea (another two being Aspidostraca and Thoracostraca), divided in to nine lesser groups.
An order of Arthropoda, including those malacostracous crustaceans that have the initial, and sometimes the 2nd, thoracic portion fused aided by the mind and bearing maxillipeds, although the continuing to be seven tend to be free and bear legs, the eyes often being sessile. Your order includes the Amphipoda and also the Isopoda.