Fig. 9. Micrographs of sections from the smolt retina following in situ hybridization with the rainbow trout UV and blue riboprobes. (A,B) Serial radial sections from the distal nasal retina show that no cone is labelled with the UV riboprobe (A) and all single cones are labelled with the blue riboprobe (B). (C–E) Tangential (C) and radial (D) sections from the mid-dorsal retina show that all single cones are labelled exclusively with the blue riboprobe, as are single cones from the temporal retina (E). The sections shown in C–E were double labelled with the UV and blue riboprobes, but only the blue riboprobe showed labelling. Symbols and nomenclature as in Fig. 5. Magnification bar (in A) is 25 µm and relates to all panels.