212 
COLOUR IN NATURE 
CHAP. 
have a scant fauna and flora are all dull of tint. 
This has been explained on the usual assumption of 
protective coloration, but it seems difficult to see 
that any explanation is necessary beyond that of 
the simple fact that in those situations the conditions 
of life are relatively unfavourable, that therefore 
dominant or brightly coloured forms are not likely 
to occur. 
2. Deep-sea Fishes .—With the colours of these 
reef-fishes we may contrast the type of coloration 
seen in deep-sea forms. These are usually remark¬ 
able for their uniformity of colouring, bands, spots, or 
stripes being rare. Dark brown or black colours 
seem on the whole to predominate, and it is not 
infrequent for the mouth and gill cavities to be very 
darkly pigmented with black. After brown and 
black colours come violet or yellowish tints, usually 
dull-coloured, although a few examples are known 
of deep-sea fishes showing considerable brilliancy of 
tint. 
3. Temperate Fishes. — It is unnecessary to 
describe the colours of the fishes found at moderate 
depths in temperate waters. The silvery iridescence 
of the lower surfaces of many, the frequency of dark 
spots or stripes, the not uncommon occurrence of 
red or orange pigments in the skin or muscle are 
familiar to all. 
In general, fishes display considerable beauty of 
colour, but usually of a somewhat fugitive type. 
Under the most favourable conditions the beauty is 
in large part lost during any process of preparing 
the skins for mounting ; and it is probably to this 
rather than to any other cause that the prevalent 
