218 MY SOMALI BOOK 



colouring, as in other characters, which prove harmful 

 to the race must eventually disappear, only those 

 surviving which are beneficial or at least harmless ; 

 and further, in view of the severity of the struggle for 

 existence, a definitely beneficial colouring of any part 

 must eventually become permanent rather than a 

 different colouring which is merely harmless. 



It inevitably follows that while the influence of 

 environment may, shall we say, have suggested existing 

 colourations, it is natural selection which has adopted 

 the most suitable of the suggestions made. The 

 necessity for protection by means of concealment is 

 believed by many naturalists to provide one of the 

 reasons for the particular selection made in any 

 individual case. Hence the theory of protective 

 colouration. 



We see, then, that Mr. Selous' theory of the influence 

 of environment on colouration may be perfectly true 

 without affecting in the least the theory of protective 

 colouration, while it can in no sense be accepted — as 

 Mr. Selous has offered it — as a substitute for the latter. 

 So that, although he does not appear to realise it, his 

 criticisms of existing theories are purely destructive, 

 since he has nothing substantial to put in their place. 



The consequence is that if we accept the results of 

 Mr. Selous' observations as proving that their coloura- 

 tion in the case of many animals has no protective 

 value, we are driven to seek — not another " cause " 

 for the production of a certain colour or pattern, but 

 another "reason" for the selection and preservation 

 of the variations which led up to that colouring. 



The only two other " reasons " that seem of 



