8 
II. N. MOSELEY. 
the fourth form was of a light pinkish red, and did not 
contain purple pentacrinin at all. 
The specimens of Pentacrinus obtained off the Ke islands, 
when in the fresh condition, had their stems almost white, 
and their crowns of a light yellow or light reddish orange, 
showing no purple coloration at all; and those dredged oft 
Panglao and Signijor islands were almost colourless; never¬ 
theless, when placed in alcohol, they yielded a solution which 
was deeply coloured of a sap green, and which, when acidified, 
became of the usual deep pink of pentacrinin. The penta¬ 
crinin was thus in these examples, though present in great 
abundance, entirely masked. It is possible that these Pen- 
tacrini would have shown an alkaline reaction in the fresh 
condition. Unfortunately the test was not made. The pen- 
tacriniu would be far less visible in the green alkaline 
condition. . . . „ 
Red pentacrinin .—The species of Pentacrinus obtained olt 
the Meangis islands, which was of a light pinkish-red colour, 
gave a simple light-red solution in absolute alcohol. This 
solution when very intense, absorbed all the spectrum except 
a band of light between E and B (PI. I, fig. 6 a). When 
the solution was weaker it showed a single broadband in the 
region of E, b and F, with some absorption of the ends of the 
spectrum (PI. I, fig- 6 b). Addition of ammonia reduced 
the brightness of the colour of the solution, and when added 
in quantity caused the absorption band to disappear. It did 
not render the solution at all green. Hence this one species 
was devoid of pentacrinin, and contained an entirely different 
colouring matter. . , 
Antedonin .—The various species oi Antedon appear to be 
usually either of a rose colour or of an orange or yellow, run¬ 
ning into a yellow brown or of a dark purple. Both the rose or 
red and yellow colouring matters are freely soluble in alcohol 
and usually in fresh water. The coloured solutions obtained 
from a large number of such species dredged by the Challenger 
were examined, but none of them yielded a characteristic ab¬ 
sorption spectrum showing bands The European species 
have been similarly found to yield a colouring matter free 
from bands. In tbs case of Antedon rosaceus all the spectrum 
but the red is absorbed. I found a purple species occurring at 
Suez to yield a similar spectrum. ... ,, 
By dredging in from 8 to IS fathoms m the channel between 
Somerset and Albany Island, at Cape York, Australia, an An¬ 
tedon was obtained in abundance which was of a dark purple 
colour The colouring matter is insoluble in glycerine, 
soluble to a large extent in fresh water, and abundantly 
