Cryptic Colouring 
we trust will be considered a fair statement of 
the various theories of animal colouration which 
are generally accepted to-day, then to show 
up the various weak points in these, and lastly, 
to endeavour to ascertain whether there are not 
some alternative explanations in certain cases to 
which the generally -accepted theory does not 
apply. 
Neo-Darwinians divide the various forms of 
colouration into three great classes :—(1) Cryptic 
colouring, or protective and aggressive resem- 
blances; (2) sematic colours, or warning and 
recognition colours; and (3) pseudo-sematic 
colours, or mimicry. A tabular statement of 
this scheme of colouring will be found on pp. 
293-7 of Professor Poulton’s Essays on 
Evolution. 
As regards class (1), Neo-Darwinians point 
out that the great majority of animals are so 
coloured as to make them very difficult to see in 
their natural environment, hence the whiteness 
of the creatures which inhabit the snow-bound 
Arctic regions, the sandy colour of desert animals, 
the spotted coats of creatures which live among 
trees, the striped markings of animals which 
spend their lives amid long grass, and the trans- 
parent blueness of pelagic animals. The theory 
is that all kinds of animals, whether those that 
hunt or those that are hunted, derive much ad- 
vantage from being coloured like their environ- 
173 
