Schematic diagrams of the eyestalks and optic lobes of C. granulatus and H. oregonensis. The anteroposterior and dorsoventral axes of the retina are equivalent to the horizontal (h) and vertical (v) axis of the retinotopic mosaic of the lamina, each of which is parallel to the transverse (TS) and longitudinal (LS) plane of sections. Abbreviations: R, retina; La, lamina; Me, medulla; Lo, lobula; LoP, lobula plate; LPr, lateral protocerebrum. Scale bar: 500 μm.