Fig. 3. Retinal location of the various cone opsins. Drawing of selected sections from a section series of Atlantic halibut larvae (40 days post-hatching). Four different halibut cone opsins probe are used. Cone distribution is indicated with colour code as follows: violet for ultraviolet- (A), blue for blue- (B), green for green- (C) and red for red sensitive-opsin. Scale bars, 0.5mm. D, dorsal; N, nasal; T, temporal; V, ventral.