branchial chamber
A B C D E F G H I L M O P R S T U V

Lateral or dorso-lateral space on each side of cephalothorax between body wall and carapace; encloses gills. In crab-like decapod, water typically enters via afferent respiratory channels near bases of chelipeds.
(M. Stachowitsch, 1992)

Alternative form for branchial chamber : gill chamber.