A small population of cones was immunoreactive to S-opsin antibody. In the single vertical sections (A1 and A2), three types of photoreceptors were identified: small rods (SRs) (arrowhead), small single cones (SSCs) (arrow), and single cone outer segments (dual arrows). The stacked images of the morphologies of SR and SSC are shown in B and C. In the wholemount retina, all SRs and SSCs with focal planes at the level of the OSM (D1), the ONL (D2), and the OPL (D3) exhibited radially oriented teleodendrites that originated from their synaptic endings (D3).