70 THE STORY OF FISH LIFE. 



The reason being, that the female by her incon- 

 spicuous colouration escaped the notice of prowl- 

 ing enemies, a great necessity when she is 

 performing the all-important task of incubating 

 the eggs. When this danger can be averted the 

 female may, and often does, assume the same 

 bright colours as her mate. 



Sometimes in place of colour we met with 

 some other form of decoration, such as simply 

 elongated feathers or wattles ; sometimes, again, 

 certain tufts or ruffles of feathers, not necessarily 

 brilliantly coloured, were developed for a short 

 time only and then discarded. Or, again, what 

 appeared at first sight to be cases of decora- 

 tion turned out, on closer examination, to be 

 instances of protective colouration. 



So is it with the liveries worn by fishes. 

 Whether dull as the proverbial ditch-water, or 

 rivalling the hues of the rainbow, there is an 

 explanation behind it. The creatures of nature 

 reflect the tone of their surroundings. 



Before all things it is necessary to observe 

 caution in formulating hypotheses to account for 

 the brilliant colouration of fishes ; or of any animal. 

 Let us take certain cases which illustrate the 

 necessity for this caution first. 



It comes natural to assume that brilliant 

 colouration, — whether permanent, as in the case 

 of parrots (to take our illustration from the birds 

 again), or seasonal, as in many of the plover 

 tribe, e.g. : the golden plover, — is to be inter- 

 preted as due either, as in the last-mentioned 

 instance, to the exigencies of courtship ; or to 

 the need for protection. Thanks to the observa- 



