34 MARVELS OF FISH LIFE 



photographed against a white background, it was 

 allowed partially to bury itself on a sand-bed, and the 

 second illustration well demonstrates the completeness 

 of its protective markings. It is very noticeable how 

 the brilliant white spots are quite as useful in concealing 

 this fish as the dark blotches. 



In all the different shadings and markings described 

 the object has been to make the fish inconspicuous, so 

 that it does not arrest the eye. Another form of pro- 

 tection is mimicry. In mimicry the fish is detected, 

 but is mistaken for something else, and so left un- 

 molested. The best illustration in our waters is that of 

 the long pipe fish, which is mistaken for a blade of sea 

 grass as its body sways in the water. A better illustra- 

 tion still is to be found in the sea-horse of Australian 

 waters. The skin of this fish is prolonged into branched 

 tags, which are shaped and coloured like the seaweed 

 amongst which it lives. 



We have alluded to the fact that fish, to suit their 

 surroundings, become rapidly light or dark by the con- 

 traction and relaxation of existing colour cells. Next 

 let us consider how by a gradual process old colour 

 cells disappear and new ones are formed, so as to alter 

 entirely the colour and markings on a fish should he 

 require an alteration in his markings to protect him 

 in new surroundings. 



As an example let us take the stone loach. This soft, 

 luscious, defenceless little fish, preyed on by beasts, birds 

 and its own predatory kindred, is to be found in every 



