COLORATION 105 



— is patternless goes to show that the nature of their 

 environment has rendered a patterned down useless. 

 That is to say, its disappearance is due, as we have 

 suggested, to the cessation of natural selection. 



The naturalist Eimer contended, some years ago, that 

 longitudinal stripes were developed to afford harmony 

 with the reed-like foliage, such as formed the dominant 

 type of vegetation in the remote past : while the develop- 

 ment of spots marks an adaptation to the requirements of 

 foliage which casts spotted shading, as is the case with the 

 plant life of to-day. But if this be true, then transverse, 

 or tiger-like, and not longitudinal stripes should traverse 

 the bodies of the young of grass- and reed-haunting birds and 

 beasts, and the survival of longitudinal stripes shows that 

 the correspondence between the markings and the type 

 of foliage need not be a close one, since longitudinal and 

 transverse stripes must both have been developed to har- 

 monise with foliage creating alternate shafts of light and 

 shadow. Thus his arguments would deprive this coloration 

 of the very virtues he seeks to claim for them ! If his 

 views as to the inter-relationship between the stripes and 

 the environment are correct, then vertical striping must 

 be regarded as the more primitive pattern, and this seems 

 contrary to fact. 



Sooner or later the further question is bound to arise : 

 " Is the coloration of the nestling to be regarded as the 

 survival of an ancestral adult livery, or of an ancestral 

 nestling livery ? And what are the factors which deter- 

 mined the evolution of this particular pattern ? " To 

 such questions we have as yet no answer. 



Finally, it may be pointed out that, while in the mammals 

 the coloration of the young commonly differs not at all, 

 or only in slight degree, from that of the adults, in 



