One of several respiratory projections that may be associated with each thoracic appendage (thoracopod). According to position one may distinguish arthrobranchs, pleurobranchs, or podobranchs; according to structure, dendrobranchs, phyllobranchs, or trichobranchs. Typically contained in branchial chamber on each side of cephalothorax.
(M. Stachowitsch, 1992)