Peracarida
plural noun
Pera·car·i·da
ˌperəˈkarədə
: a division of Malacostraca including among others the amphipods and isopods all having the first thoracic segment fused with the head, the thoracic legs flexed between the fifth and sixth segments, and the young developed in a brood pouch from which they escape at a late stage
Word History
Etymology
New Latin, from Greek pēra pouch, bag + New Latin -carida (from Latin carid-, caris, a kind of sea crab)