Eumalacostraca Grobben, 1892
* C. Grobben (1892). Zur Kenntnis des Stammbaumes und des Systems der Crustaceen. Sitzber. K. Akad. Wiss., Vienna, Math. Nat. Cl. 101: 237-274.
The Eumalacostraca (Greek: "true soft shell") are a subclass of crustaceans, containing almost all living malacostracans, about 22,000 described species. (The outgroups are the Phyllocarida and possibly the Hoplocarida or mantis shrimps.)
Eumalacostracans have 19 segments (5 cephalic, 8 thoracic, 6 abdominal). The thoracic limbs are jointed and used for swimming or walking. The common ancestor is thought to have had a carapace, and most living species possess one, but it has been lost in some subgroups.
Martin and Davis  present a classification of living eumalacostracans into orders, to which extinct orders have been added, indicated by †.
The group as originally described by Karl Grobben  included the Stomatopoda (mantis shrimp), and some modern experts continue to use this definition. This article follows Martin and Davis in excluding them; they are placed in their own subclass, Hoplocarida.
Source: Wikispecies, Wikipedia: All text is available under the terms of the GNU Free Documentation License