LIGHT INTENSITY AND MELANOPHORE RESPONSE IN THE MINNOW, ERICYMBA BUCCATA COPE

Abstract

1. A quantitative method of determining the influence of the environment upon the melanophores of small fishes is described. 2. The degree of dispersion of the melanin in the melanophores of the silver-mouthed minnow, Ericymba buccata, is within certain limits determined by the total light intensity as well as by the shade of the background. 3. Upon a constant black background between the intensities of light, .000053 and 1.75 foot candles, the average diameter of pigment masses is directly proportional to the logarithm of the light intensity. 4. At an intensity of less than .000053 foot candles the fish are at their maximum degree of paleness in spite of a black background. 5. At 1.75 foot candles illumination the fish becomes maximally dark upon a black background, and the average diameter of melanin masses appears to vary in a directly proportional fashion with the ratio, [see formula in the PDF files], which reaches the eyes of the fish.