THE COLORATION OF FISHES. 33D 
The Coloration of Fishes. 
By W. AnprErson SMITH. 
[Read 3lst March, 1896.] 
THE question of the coloration of all animal and vegetable life is 
one that has occupied the minds of naturalists more and more of 
recent years, since Darwin brought so prominently forward the 
remarkable instances of colouring evidently for a special purpose, 
and directed inquiry into fresh channels. 
If we reason from analogy, there are various groups of causes 
that produce marked colour effects on the animal and vegetable 
world ; and as the dividing line between these two kingdoms is 
intangible, and the characters intercross, it is reasonable to sup- 
pose that similar causes are at work throughout the living world 
of Nature. It does not at all hold good, however, that the most 
common and apparent cause is the one that is always uppermost, 
and the most reasonable and readily suggested may also be far 
from the real one. 
In this paper I neither pretend to pose as original or final, but 
seek to state succinctly my views on an interesting problem, in 
the hope that it may stimulate other workers in the same field, 
and perhaps prove suggestive or directive. 
The first general principle we may safely accept is that of light. 
There is no question that tropical and inter-tropical fishes are more 
brilliantly coloured than those of the zones more temperate or less 
. within the influence of the sun. No one acquainted with the 
brilliant hues of fishes from the warmer seas can question this, 
and the influence of light as a decorative agent consequently holds, 
in my opinion, the first place, however otherwise modified. There 
are some curious apparent exceptions to this, some of which I will 
refer to; but broad principles must be based on broad areas, and 
although we may not be able to explain the exceptions to our 
satisfaction that does not make them inexplicable. On the same 
