54 Cc. A. MAO MUNN. 
before extracting the pigment from the rest of the body. 
Krukenberg calls the above red pigment “ Comatulin,” and 
says that it and that of yellow and brown species are soluble in 
sea-water and in diluted alcohol, but insoluble in glycerine, ether, 
chloroform, benzol, bisulphide of carbon, turpentine, and almond 
oil, and that it only goes over into these solvents when water is 
present. I did not dry my specimens completely, which may 
account for the discrepancy in our results. The red, brown, 
and yellow pigments from correspondingly coloured specimens 
of Antedon, all are related to each other according to Kruken- 
berg, and none of them yielded an absorption band. One finds, 
he says, that an extract of red comatulin by dilution becomes 
more yellowish, of yellow more red by concentration ; and if 
one evaporate a red feebly coloured purple solution of 
comatulin (in dilute alcohol) on the water bath and expose 
the residue to the light, the cherry-red colour changes first 
into an insignificant brown yellow, and this behaves ex- 
actly like the pigment obtained from brownish-yellow varie- 
ties of Comatule; it then gets lighter in colour until it 
becomes bleached. Diluted aqueous solutions of comatulin 
also, according to him, suffer a similar change, but alcohol solu- 
tions are more stable. He also says that aqueous and alcohol 
solutions are coloured orange to brownish yellow by hydro- 
chloric and acetic acids, and the colouring matter separates ; also 
that alkalies such as potash or ammonia precipitate the colour- 
ing matter with unchanged colour. Respecting the presence 
of a band in red he says :—‘‘ Lasst man die Comatulen wochen- 
lang in Alkohol liegen, so erhalt man Farbstofflosungen, welche 
mehr oder weniger deutlich ein Absorptionband vor C erken- 
nen lassen; dieses Spectralband Charakterisirt bekanntlich 
Hepatochromate vieler Evertebraten und es ist deshalb sehr 
wahrscheinlich, dass dasselbe auch bei Comatula den Leber- 
zellen entstammt; sicherlich entspricht dasselbe keinem Haut- 
farbstoffe, speciell nicht dem Comatulin, denn ein Spectrum tief 
purpurrrother, rasch bereiteter alkoholischen Ausziige der 
Arme fehlt das Absorptionsband standig.”” The reason why 
the alcohol took a week to extract the so-called “ hepato- 
