10 H. N. MOSELEY. 



rendered transparent and mounted in Canada balsam as 

 adhering to the filtering paper. This precipitate when thus 

 dried yields the same spectrum as it does when suspended in 

 the solution. The spectrum consists of two bands as figured 

 (PL II, fig. 7^). . _ 



The dried precipitate is insoluble in water, ether, and 

 alcohol, but soluble in acidified alcohol, and then gives the 

 original acid spectrum (PI. I, fig. 7 c), and when this solu- 

 tion is carefully neutralised the original three-banded spec- 

 trum returns, but I obtained it only faintly. Though a 

 very large quantity of precipitate was removed by ammonia 

 from a strong and original alcoholic solution, the solution 

 still remained of a vivid colour and gave its three bands. It 

 was only after continued addition of ammonia that the whole 

 of the colouring matter was precipitated. 



The colouring matter appears to require a proportionately 

 increased quantity of ammonia to precipitate it, as the solu- 

 tion becomes weaker. Both the dried colouring matter 

 and the alcoholic solution have maintained their colour and 

 properties unimpaired after a lapse of two years. 



Hymenaster. — Several new species of this deep-sea genus 

 of Sir C. Wyville Thomson were obtained by the Chal- 

 lenger from deep water. They are of a brilliant scarlet 

 colour when fresh, and the colour is rapidly discharged in 

 alcohol. The resulting deeply coloured solution yields, how- 

 ever, no absorption bands, but a spectrum in which all the 

 light except the red is sharply cut off. Many other brightly 

 coloured star-fish were examined, but with a similar result. 



Hoplacanthinin. — Several specimens of an echinoid of the 

 genus Hoplacanthus were obtained by H.M.S. Challenger. 

 They are of a dark madder colour. Observations were 

 made on specimens obtained in latitude 6°48' N., longi- 

 tude 122°25' E. from 800 fathoms, October 23rd, 1874. 

 The colouring matter is freely soluble in alcohol, yielding a 

 madder-coloured solution, which shows in the spectrum two 

 not very sharply defined bands (PL II, fig. 8). The colouring 

 matter became precipitated in the alcoholic solution when 

 left to stand in about twelve hours. The absorption bands 

 could not be obtained from the precipitate. 



Antedoninfrom Holothurian. — On Feb. 26th, 1874,in latitude 

 62°26', longitude 95°44' E., in the extreme south of the South 

 Indian Ocean, a large Holothurian, with a gelatinous test, was 

 dredged from 1975 fathoms. The holothurian was about ten 

 inches long, and three or six broad. The animal was of a 

 uniform dark purple colour. The colouring matter present 

 appeared to be identical with that obtained from the Antedon 



