REPORT ON THE CRINOIDEA. 129 
The other species, besides these two which were dredged at Station 214, off the 
Meangis Islands, were Metacrinus costatus, Metacrinus moseleyi, Metacrinus varians, and 
Metacrinus wyvillii. As this last also occurred at Station 170, off the Kermadec Islands, 
it was probably one of those which were coloured dark purple, owing to the presence of 
acid pentacrinin. Prof. Moseley can give me no clue, however, as to the anomalous 
form which did not contain pentacrinin at all, but an entirely different colouring matter. 
It was of a light pink colour when fresh, and when treated with absolute alcohol gave a 
simple, light red solution, with an absorption spectrum totally different from that of 
pentacrinin. 
All Prof. Moseley’s spectroscopic observations of the colouring matter of the 
Pentacrinidze were made in the Pacific ; and it therefore became a matter of some import- 
ance to determine the presence of pentacrinin in the Atlantic species of the family. For 
this purpose Prof. Moseley has been kind enough to examine some of the deeply 
coloured spirit in which there had been preserved several individuals of Pentacrinus 
wyville-thomsoni that were dredged by the “ Porcupine ” in 1870, off the coast of Portugal. 
As might have been expected, the colouring matter proved to be pentacrinin. 
A still more interesting point is the presence of this substance in Holopus. Immersion 
of a dry, greenish-black Holopus in alcohol for a few minutes yielded a dichroic solution, 
which gave the characteristic spectrum of pentacrinin. It is more than probable, there- 
fore, that this substance will be found to be present in the four Caribbean species of 
Pentacrinus. 
Most species of the Comatulze “appear to be either usually of a rose colour or of an 
orange or yellow, running 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 colouring matter of most of them, like that of Antedon rosacea, has no characteristic 
absorption spectrum showing bands. But a dark purple species common at Cape York 
yielded a special colouring matter which Prof. Moseley has termed ‘‘Antedonin.” It is 
freely soluble in weak spirit, and gives an intense fuchsin-coloured solution, which yields 
spectrum consisting of three well defined absorption bands. 
I have little doubt that the species in question was Actinometra strota. Two species 
of Antedon which were also obtained at Cape York, but in less abundance, seem to have 
been tinged with the same colouring matter, as their appearance is the same as that of 
the Actinometra. The most remarkable point about this colouring matter is its presence 
in a slightly modified form in various deep-sea Holothurians. 
(ZOOL. CHALL. EXP,—PART XXxuI.—1884.) ily 
