Fig. 9. Electron micrographs of photoreceptor outer and inner segments. Note that the stacked membrane discs of the rod outer segment (ROS) are separated from the overlying plasma membrane (*), while the membranes of the cone outer segment (COS) are continuous with the surface membrane. Arrowheads indicate basal membrane infoldings; cc, connecting cilium; bb, basal body; m, mitochondrion. Bar = 0.5 μm.