v COLOUR-PHENOMENA IN WORMS 105 
was called chlorocruorin by Professor E. Ray Lan- 
kester, who stated that it is capable of existing in 
an oxidised (green) and a reduced (red) condition. 
Krukenberg denies this and regards the appearances 
observed by Professor Lankester as due to the 
marked dichroism of the green solution. The 
solution exhibits a two-banded spectrum, and the 
pigment is destroyed by strong acid or alkali. 
In connection with the supposed respiratory 
function it is perhaps worth notice that, according to 
Paul Langerhans, the colour of the blood in Sabella 
variabilis may vary from a clear yellow-green to a 
dark brown ; while it is an old observation that in 
worms in general the colour of the blood varies 
much, being very frequently different in the various 
species of a genus. 
Another interesting green pigment is that which, 
as we have already noticed, colours the aberrant 
worm Chcetopterus. This pigment is of greenish 
colour, and is confined to the walls of the anterior 
part of the alimentary canal. Like bonellin and 
“ enterochlorophyll,” it gives a complex, exceedingly 
beautiful spectrum which changes on the addition of 
alkali or acid, and it in other respects shows a relation 
to these two pigments. 
Another green pigment of brighter tint but ap¬ 
parently of simpler nature occurs in Eulalia viridis, 
and probably in other forms. In Eidalia itself it is 
apparently intermixed with a yellow pigment, but 
in the eggs occurs pure. It is soluble in water 
and alcohol, turns slightly blue with acids, and is 
destroyed by strong alkali. It closely resembles 
the green pigment of Thalassema already mentioned. 
