52 THE HAUNTS OF LIFE 
violet, brown, and green, and it is often 
almost perfectly self-camouflaged among 
brightly coloured seaweeds. 
Not less subtle is the rapid change of 
colouring and pattern in flat fishes like plaice 
and dab. Very quickly they put on the hue 
and the marking of the sand or shingle on 
which they are resting. When on sand they 
usually cover themselves quickly, all except 
the eyes which protrude and look about. 
Blind flat fishes do not change colour, so we 
know that the message from the outside world 
first affects the eye. It travels to the brain, 
and by the nervous system to the colour-cells 
in the skin which can change their size and 
position. In some instances the change oc- 
curs in a minute or two, and it gives the fish 
a garment of invisibility. 
In the aquarium at New York there is 
often a startling display of coral-reef fishes 
from the Bermudas and similar places. Their 
colours are brilliant, and their patterns are 
almost incredible. It seems to some natu- 
ralists quite impossible that these colours and 
patterns can have concealing value, partly 
because they are so conspicuous, one might 
almost say daring, and partly because they 
