V 
COLOUR-PHENOMENA IN WORMS 
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regular intervals by the strong circular muscles, so 
that the stripes which would be formed at the spaces 
between the longitudinal muscles are interrupted. 
These suggestions are exceedingly interesting and 
ingenious, and of obvious importance in relation to 
the origin of markings. In view of the origin of the 
pigment from the blood, it would be very interesting 
to know whether it is in any way derived from 
haemoglobin, and also whether that transfer of pig¬ 
ment from the gut to the surface which occurs when 
the leech is fed with carmine, ever occurs during the 
ordinary course of affairs. 
The process described by Graf presents some 
interesting analogies to that described by Eisig for 
the Capitellidae. An inquiry into the causes which 
determine the marked differences in colour between 
the leeches and the Chsetopoda would be very inter¬ 
esting, but does not appear to have been attempted. 
The Pigments of the Polyzoa, and the 
Origin of Pigmentation 
In connection with the colours of worms there 
are a few points about the pigments of the Polyzoa 
which are of interest. 
The Polyzoa are aberrant worms, which form 
colonies consisting of numerous polypides embedded 
in cells or chambers, which, being united together, 
constitute the coenoecium or substance of the colony. 
The coenoecia of Flustra , the sea-mat, are very 
familiar objects on our own shores, where they are 
often mistaken for seaweed. Each cell or chamber 
with its contained polypide is known as a zooecium. 
