294 
COLOUR IN NATURE 
CHAP. 
with this. The following table shows the results 
obtained from some of these experiments :— 
PIGMENTS INTRODUCED INTO ALIMENTARY CANAL 
Organisms. 
Situations in which in¬ 
troduced Pigments are 
found. 
Natural 
Analogues. 
Observer. 
Polyzoa. 
In “hepatic cells” 
of gut. 
Brown pigment 
of these cells. 
Harmer. 
Crustacea. 
In cells of hepatic 
caeca, ultimately in 
faeces. 
Pigment nor¬ 
mally found in 
hepatic cells 
and feces. 
Cuenot. 
Capitellidae. 
In cells of gut, ulti¬ 
mately in skin. 
Pigment nor¬ 
mally occur¬ 
ring in cells 
of gut and in 
skin. 
Eisig. 
Oligochaeta 
( Tubifex). 
In the so - called 
chloragogenous cells 
covering the intes¬ 
tine, ultimately in 
the skin. 
(?) Pigment of 
chloragogenous 
cells and of 
skin. 
Cuenot. 
In these cases the Capitellidae are the only forms 
in which the introduced pigments come to have a 
marked effect on the coloration. Another case in 
which the introduced pigment is important in this 
way is perhaps the case of caterpillars, where the 
pigment introduced with the food reaches the 
connective tissues and so the skin. In the general 
case, however, it would seem that the pigments 
which normally result from the activity of the liver 
or “hepatic cells,” as well as pigments artificially 
introduced into the gut, are usually directly eliminated 
by means of it, and do not become important in 
