8 H. 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 off 

 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, Avhen 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 Avould have shown an alkaline reaction in the fresh 

 condition. Unfortunately the test was not made. The pen- 

 tacrinin would be far less visible in the green alkaline 

 condition. 



Red 2ientacrinin. — The species of Pentacrinus obtained off 

 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 broad band 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. 



Antedotiin. — The various species of Antedon appear to be 

 usually either of arose 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 the 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 12 fathoms in 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 



