Ultraviolet receptors, tetrachromatic colour vision and retinal mosaics in the brown trout (Salmo trutta): age-dependent changes.

Microspectrophotometric analysis of the visual receptors of "yearling" brown trout, Salmo trutta, revealed three cone types, double cones with visual pigments absorbing maximally at about 600 and 535 nm, and two types of single cone with lambda max at about 440 and 355 nm. Two-year-old fish did not possess the u.v. cone cells. Microscopical analysis of the… CONTINUE READING