[Cephalopoda] The leaf-like convoluted individual components of the gill through which gas exchange occurs (Ce 1I). In Order Decapoda and Order Octopoda (other than cirrates) the inner and outer demibranchs of the gills are attached to a narrow central axis and are typically arranged vertically in two diverging rows, or oriented parallel to the gill axis (lamellae perpendicular to axis). In cuttlefishes the gills have free lamellae (not attached at the tip) and no branchial canal.