1903 Colour in Fishes 213 



suggest that its most obvious appeal to the appreciating eye 

 is made in the world of fishes. Occasionally, indeed, it 

 has seemed to me that the doctrines of colour protection 

 are a little strained by those who interpret nature in her 

 varying solicitude for her children's welfare. How, for 

 instance, the large brown egg of the cuckoo can be regarded 

 as helped by its coloration when lying in a nest of green 

 moss along with the small blue eggs of the hedge-sparrow, 

 I never understood. 



The fishes offer no such anomalies. Those which, like 

 the cods and flat fishes, swim low against a background of, 

 for the most part, sand or shingle are dull coloured above, 

 and it takes a practised eye to distinguish a plaice, even 

 with the additional assistance afforded by its red spots, 

 lying motionless in even two or three feet of water. Often 

 enough, when the spearer wades after his prey, it is only 

 the sudden movement of the latter, disturbed by his ad- 

 vancing feet, that betrays it to the enemy. If the plaice 

 had only the useful inspiration to lie still, it would in most 

 cases go unharmed. 



With shoaling fishes, like the herring and mackerel, 

 the needs are as different as their mode of life. These 

 swim close to the surface. Their most dreaded enemies, 

 the hake and dogfish, are on the prowl beneath them. Con- 

 sequently, their victims are between them and the light. 

 What is more likely to enable them to pass on their way 

 unseen than the silvery coat which nature has given them 

 for the purpose ? Even the bars on the mackerel assimilate 

 wonderfully with the lights and shadows in the surface 

 waters. 



With the larger fishes, it is true, such as the huge 

 sharks, which have little to fear from natural enemies, 

 there is evidence of carelessness in this matter of colouring, 

 and so we find some of the dogfishes fearlessly swimming 

 abroad in spotted uniforms that recall the leopard of the 

 dry land. 



Others again, such as the gorgeous wrasses, are not 

 palatable to a number of carnivorous fishes that prey 

 readily on other kinds, and these can therefore afford to 

 wear coats of many colours. Even so, however, it is re- 



