MISCELLANEOUS NOTES. 1M13 



■entirely neglected. But a point must come when it is no longer negligible, and 

 now its influence must inevitably be either harmful or beneficial to the anima<. 

 Here natural selection steps in. If the variation is definitely haimful it can- 

 not endure, if. on the contrary, it is beneficial it will be handed down and 

 become permanent. I leave out of count such variations that may arise by 

 correlation. These in no sense affect the argument, for it then becomes merely 

 a question of which of the correlated variations exercises the more potent 

 influence. 



The mere fact that animals are usually coloured in harmony with their 

 surroundings is no disproof of protective colouiation as our authors would 

 infer, fur, obviously, to be protected by its colour the animal mint hr iv harihony 

 mth its environment, subject to certain exceptions that will be dealt with anon. 



No one, as far as I know, claims that an animal attains a certain colour or 

 marking in order that its colouration should serve as a protection. But rather 

 because it has tended towards a similarity with its environment, natuial selection 

 preserves and intensifies the similarity. 



There can be little doubt that variations occur in a direction away from the 

 general colour scheme of the environment but it is exactly those variations 

 that natural selection tends to suppiess, unices they subserve some other and 

 more important purpose, or the same purpose in another way. 



So it may be seen that it is precisely where the hypothesis of protective 

 colouration might fail that that of colouration by the influence of the envi- 

 ronment would also fall short. 



It is, however, quite possible that environment (in conjunction with other 

 causes) gives the first impetus towards protective colouration and this is then 

 seized upon and worked up by natural selection, which in itself, of course, is 

 incapable of initiating a variation. 



Dnles's it can be proved that it is of advantage in resisting climatic rigours, 

 there is no intrinsic value to an organism in being colouied in haimcny with 

 its environment. But where such colour:is protective against its enemies or 

 facilitates the obtaining of its food, the benefit is distinct and it will be 

 perpetuated. 



One of the points both authors wish to make in disproof of protective 

 colouration, is that it can only be effective when animals are motionless, and 

 that they betray themselves as soon as they stir, even if it be only a switch of 

 the tail. This is obvious and it cannot be contended that protective colour- 

 ation conceals the animal at all times and under all conditions. In the nature 

 of things this is out of the question for any being less well endowed than the 

 chameleon, and even that reptile requires a little time. But an attentive 

 perusal of Mr. Selous' book will show that protectively coloured animals do 

 benefit by their colouration. It must also be within the experience of eveiy 

 big game hunter to have intently gazed upon an animal whose coat blended 

 with the back ground without seeing it until it has suddenly dashed oft', giving 

 no chance of a shot. 



