CHAPTER XI 

 COLORATION 



Colours of some tropical fishes. Variations. Meanings of coloration. 

 Obliterative shading. Oceanic fishes. Shore fishes. Fishes of coral 

 reefs. Protective resemblance. Mimicry. Coloration and environ- 

 ment. Colour changes. Sexual differences. Warning colours. 

 Mechanism of coloration: chromatophores, iridocytes, etc. Mechan- 

 ism of colour changes. Xanthochroism. Influence of light on 

 pigment. Coloration of Flat-fishes. Ambicoloration. Albinism. 



The pallid corpses displayed on the fishmonger's slab, or the 

 stuffed and often faded specimens in the local museum, give 

 but a poor idea of the colours of living fishes, and are responsible 

 for the popular impression that in the matter of vivid hues 

 fishes cannot challenge comparison with such creatures as the 

 birds and butterflies. The difficulty of observing fishes in their 

 natural surroundings is a real one, but the opening of the 

 aquarium at the Zoological Gardens has done much to remove 

 this, although, even here, the surroundings are necessarily to 

 some extent artificial. Nevertheless, the beautiful colouring 

 of many of its inhabitants has proved a revelation to visitors, 

 and a survey of some of the fishes found in the neighbourhood 

 of coral reefs would remove once and for all the erroneous 

 impression that most forms wear comparatively dull liveries, 

 an impression that has been further fostered by the fact that, 

 with certain exceptions, the inhabitants of our own coasts and 

 rivers are rather soberly coloured. 



Many pages would be required to describe even a few of the 

 brilliant and fantastic combinations of colour encountered in 

 tropical fishes, but a few examples should suffice to give some 

 idea of their possibilities. Mr. Saville Kent, who has made a 

 special study of the fishes of the Barrier Reef of Australia, 

 describes a Sea Perch or Grouper (Epinephehis) with a pre\ ailing 

 ground colour of brilliant carmine with a tendency to yellow 

 on the lower parts, and with numerous ultramarine spots of 

 brilliant intensity on the sides. Another fish (Beryx), belonging 

 to the tribe of Berycoids, has the same vivid ground colour, but 

 with various opalescent tints, chiefly reflections of blue and 

 lilac. One of the Thread-fins (Polynemiis) is coloured chrome 



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