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 CfuEtopterus. 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 Eulalia 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. 



