Colored bowls evoked characteristic chromatophore responses in Gobius minutus, Labrus ossifagus, and Pleuronectes platessa. The responses, including those to blue and to yellow, effected differential adaptation of integumentary hue as well as shade, especially in the goby and the plaice. They confirmed that erythrophores, xanthophores, and melanophores may act independently, pigment dispersal in erythrophores and xanthophores depending on the color of the bottom while melanophores respond according to its darkness.The changed chromatophore behavior resulting from fin cuts producing denervated bands indicated that the melanophores, erythrophores, and perhaps the xanthophores are innervated at least by concentrating fibers in the goby and that the erythrophores and melanophores are probably innervated in the wrasse.Denervation experiments supplied evidence consistent with the hypothesis that dispersing as well as concentrating nerves and their neurohumors control the goby's melanophores and erythrophores an...