Fig. 5. Micrographs of sections from the retina of the alevin following in situ hybridization with the rainbow trout UV and blue riboprobes. (A–D) Serial sections from the dorsal retina show a full square mosaic in which all single cones are labelled by the UV riboprobe (A,C) and none are labelled with the blue riboprobe (B,D). (E–H) Serial sections from the lower ventral retina show that most single cones are labelled by the UV riboprobe (E,G) but some are also labelled with the blue riboprobe (F,H). d, double cone; other symbols and nomenclature as in Fig. 2. Magnification bar (in A) is 25 µm and relates to all panels.