chap, v COLOUR-PHENOMENA IN WORMS 97 
The only detailed investigations on the pigments 
of Turbellaria appear to be those of Moseley, who 
made some observations on two species of Rhyncho- 
demus found in New South Wales. Of these one 
was blue and the other red, the two living together 
under somewhat similar conditions. The blue 
pigment was insoluble in alcohol, turned red with 
acids, and then dissolved in alcohol ; alkali restored 
the blue colour. This at once suggested that the 
red pigment was due to an acid reaction in the tissues 
of the red species, and was simply a modification of 
the blue. Moseley could not, however, succeed in 
turning the red pigment blue with alkali, and found 
that it was insoluble in acidified alcohol. He was 
forced therefore to the conclusion that the two 
pigments are entirely different ; no further investiga¬ 
tion seems to have been made on the subject. 
It is interesting to note that in spite of the 
simplicity of the Turbellarians, the coloration is not 
necessarily completely uniform, but may show an 
arrangement into bands and spots. Thus the species 
of Geoplana often show a dorsal stripe of green, 
orange, or purple, while the rest of the body may 
show spots of blue, brown, or yellow on a dull 
ground. 
The pigments of the Nemertea have been even 
more neglected than those of the Turbellaria, though 
with less excuse. We quote the following eloquent 
description of their colours from Professor Mffntosh’s 
monograph :—“ The colours of many species of the 
group are of such beauty as to attract even the 
casual observer, while in this respect also they widely 
deviate from their supposed allies the parasitic 
H 
