Fig. 2.
Rhabdom structure and orientation at various retinal levels in the dorsal rim area (DRA) of the compound eye. a, b, d, e Transmission electron micrographs of rhabdom cross sections in the DRA (b, e) and, for comparison, of the unspecialized dorsal area (DA; a, d) at distal (a, b) and proximal levels (d, e) of the retina (V vertical cells [receptors 1, 5], H horizontal cells [receptors 3, 7], D diagonal cells [receptors 2, 4, 6, 8]). Bar 1 μm.c, f Light micrographs of eight identified DRA ommatidia (circled) at a distal (c) and a proximal (f) retinal level (red lines border between DRA and unspecialized DA). Note the almost identical orientations of the rhabdom transverse axes (long axes of the rectangular rhabdom cross sections) relative to the eye margin (top) at the two retinal levels. Bar 20 μm