20 
II. N. MOSELEY. 
When large numbers of Flabellum variabilc were dredged 
by us in the Arafura Sea a considerable number 1 were always 
found to be entirely devoid of pigment and pure white, the 
corallum itself even being colourless. Similarly amongst 
300 or 400 specimens of Renilla (violacea ?) which were 
dredged in the mouth of the La Plata, off Monte Video, one 
specimen was found to be of a pure white, all the remainder 
being of the deepest violet. In ordinary vertebrate albinos 
only skin pigments are affected; but in what may be re¬ 
garded as albino genera, such as the fish Leptocephalus and 
in the pelagic Plagusia, even luemoglobiu has disappeared. 
Colouring matters must have a pedigree and a develop¬ 
mental history which will, in some instances, be able to be 
traced in the same manner as that of an organ of the body 
or an histological tissue. A pigment thus may become 
developed at the root of a zoological phylum, persist in some 
branches, die out in others, and in some possibly reappear 
by heredity. The existence of Polyperythrin in both Acti- 
nozoa and Hydrozoa amongst Ccelenteratcs, and its very 
irregular but nevertheless wide-spread distribution amongst 
these, seems to be only explicable on such an hypothesis. It 
is quite possible that the tracing of zoological relations may 
be facilitated by the use of the spectroscope. A careful 
chemical examination of some of these numerous colouring 
matters which do not in the fresh condition yield banded spec¬ 
tra would, no doubt, give evidence of their being transitional 
to certain of the more complex colours, which latter might pos¬ 
sibly be produced from them artificially by action of reagents. 
Most Echinoderms are endowed with intense colouring 
matters yielding a spectrum, in which nearly all but the red 
or red and a little yellow is absorbed. Since some few forms 
in each group of the Echinoderms, except the starfish, have 
colouring matters yielding banded spectra, and the same 
colouring matter, Antedonin, occurs in so widely separated 
forms as Ilolothuria and Antedon, it is quite possible that 
in most cases a mixture of colouring matters masks a pig¬ 
ment common to many members of the group, and yielding 
a banded spectrum. The examination of the colouring of 
young animals might yield interesting results. At the same 
time, no doubt, many colouring matters may have had an 
entirely isolated formation, as in the case of Turacin, to 
which there seem to be no stepping-stones; and the necessary 
1 It even became a question whether the majority of specimens were not 
unpigrnentcd, in which case the exhibition of pigment or chromatism—as it 
might be termed, in antithesis to albinism—would become the exceptional 
variation m the species instead of the rule. 
