226 
ANIMAL COLOURING 
goes without reward. His researches were devoted to 
the history of a small group of sea-worms. One of 
these he found living parasitically upon a marine 
sponge in the Bay of Naples. The sponge was of 
a yellow colour, caused by the presence of small 
particles of colouring-matter. The worm was of the 
same colour, with bright orange spots, and the pigment 
which coloured the sponge was found to be the same 
which coloured the worm, having been simply trans- 
ferred from the tissues of the sponge to the skin of 
the worm, after going through part of the alimentary 
canal. Dr. Eisig is of opinion that the “ pigment’" 
so transferred from the alimentary canal to the skin is 
itself the cause of the creature being distasteful, which 
suggests the conclusion that the brilliant colour — that 
is, the secretion of a quantity of colouring-matter — 
has itself caused the inedibility of species, rather than 
that the inedibility has made necessary the production 
of bright colour as an advertisement. “This ex- 
planation,” Mr. Beddard remarks, “ is not entirely 
contrary to the views of Wallace, Poulton, and others; 
for we may still suppose that the bright colours are 
actually ‘ warning’ colours, although they have not 
been evolved for this purpose.” But the weakness, as 
well as the attraction, of the unmodified theory really 
lies in the supposition of the creation in the creature 
of colour, for the express purpose of advertisement. 
The modest conjecture of Dr. Eisig transfers the 
explanation to safer ground. 
The mode by which, in the simple organisms which 
