THE GREAT DEEPS 129 
large luminous plates just under its eyes. One 
of these gives off red light and the other 
green, and from the arrangement of the mus- 
cles connected with them, it is thought that 
the fish has control over them, and can turn 
on its lamps at will, to warn off its enemies 
or to aid it in the search for its prey! 
“Very strange indeed would be the appear- 
ance of these animals if we could see them in 
the deep! In the absolute darkness of the 
abyss they would appear as ghostly, silver- 
blue shapes, glimmering like an electric lamp 
through dense fog on a dark, moonless night. 
Of all the characters of deep-sea fishes this 
almost universal phosphorescence is the 
strangest.” 
Another puzzle may be found in the fact 
that many deep-sea animals are brightly col- 
oured. Bright red is common, for instance, 
in crustaceans, star-fishes, and sea-anemones. 
There is very little in the way of pattern, but 
there is not a little colour. What can be the 
meaning of colour in a world of darkness? It 
is highly probable that the colours as such 
have no significance in the life of these deep- 
sea animals, that they are simply the useless 
by-products of some of the fundamental proc- 
