THE ZOOLOGIST 
No. 687.—September, 1898. 
BIOLOGICAL SUGGESTIONS. 
ASSIMILATIVE COLOURATION. 
By W. L. Distant. 
Part I. 
Mr. Darwin admits that there are unknown laws of development and 
variation, and certain direct actions of external conditions, which to some 
extent modify animal forms; but, so far as yet known, these can only 
be permanently preserved or increased, when useful, by means of natural 
selection. We are not now discussing whether this view is strictly correct, 
or whether there are not probably unknown laws determining the lines of 
directions in which alone natural selection can profitably and permanently 
act. There may be such, and the present writer is disposed to think there 
are such ; but these have not beeri proved to exist.—A. R. WALLACE. 
We are not enunciating ascertained truths; we are simply recording the 
results of study.—G. H. Lewes. 
Any student of natural history who cares to analyse the vast 
strides made by his science during the last thirty years must be 
impressed by the great advance which has taken place in the 
philosophical conception of the origin of animal colouration. 
** Protective resemblance,” ‘‘mimicry,” and “utility markings” 
are now by-words with every naturalist, whilst some scientific 
theory has replaced much teleological wonder. Although our new 
views are in very many cases explanations of old observations, 
these views have in friends and foes alike created such a host of 
good observers, who are anxious to support or demolish advanced 
Zool. 4th ser. vol. II., September, 1898 2¢ 
