92 
COLOUR IN NATURE 
CHAP. 
at least can be made to yield very bright green 
derivatives. 
Dr. M‘Munn (1885) has described by means of 
the spectroscope a number of other pigments in sea- 
anemones, but too little is known of these to make it 
profitable to detail here their names and properties. 
There is, however, one interesting pigment, called by 
Moseley polyperythrin, which deserves further notice. 
Moseley found this pigment in a number of simple 
stony corals and in a few anemones and jelly-fish, 
almost all from deep water. It is of a deep madder- 
brown colour, and in the case of the corals sometimes 
coloured uniformly both the soft parts and the coral, 
sometimes the soft parts only. Further, in some 
specimens it was uniformly distributed, while in 
others it occurred in streaks or was totally absent. 
The pigment dissolves in acidulated alcohol or in 
dilute acid to form a pink solution with green 
fluorescence, and gives a spectrum which in some 
respects resembles that of the pigments of the 
chsetopterin group. It seems not improbable that 
this pigment is the result of the modification of a 
pigment allied to the “ chlorophyll ” of Anthea. 
Another interesting series of pigments, apparently 
not allied to the preceding, are those producing the 
blues and browns of the surface jelly-fish. There is 
reason to believe that the blue colour of Cyanea , of 
the common Aurelia , of Rhizostoma , and of Vellela 
are all due to a pigment called by Krukenberg 
Cyanein, which is recognised by the following 
characters. It is soluble in water, especially in 
water containing neutral salts ( e.g . sea-water). It is 
unaltered by weak acids, but strong acid, alcohol, 
