282 NATURAL HISTORY OF OUR SHORES 



to interfere with, and yet might by mistake be attacked. 

 It prevents the liability to such mistake by assuming 

 some conspicuous colouring, to remind the enemy that has 

 once ventured to attack it that it is not good to do so. 

 This is termed warning colour. 



The third is that colour, or arrangement of colours, re- 

 ferred to sexual selection, in which their use is to entice or 

 charm the opposite sex. 



The fourth when the conspicuous colour serves to lure prey 

 (or in the case of flowers to lure insects to render service). 



As a general rule all these are well-established facts, 

 and illustrations in support could be supplied by the 

 thousand. Some of them are strikingly obvious to the least 

 observant. Who, for instance, has not seen a kitten or a 

 puppy catching flies, and noticed that if a wasp comes 

 within range it is generally left to go unmolested, or even 

 causes the retreat of the fly molester. 



The conspicuous yellow banding is impressed upon the 

 senses of the kitten or the puppy, not necessarily by ex- 

 perience of its own, but by that of some of its ancestors, 

 which noted the connection between the " yellow bands " 

 and the pain their owner could inflict, and then handed 

 down, in the form of that hereditary memory we term 

 " instinct," their experience to their offspring. 



This is a homely illustration of the use of " warning 

 colour." The use of mimetic colouring is still plainer. 



If a creature were good to eat, had no means of defence, 

 had enemies present, and was conspicuous, then, obviously, 

 it would soon not be, unless, indeed, its reproductive powers 

 were such as to bear the toll. 



It seems that the above series of uses of colour were 

 broad enough in their provisos to cover all cases, but let 

 us try to apply them to the red sponges. 



Mimetic colouring is out of it : they are strongly con- 

 spicuous. 



