so H. N. MOSELEY. 



When large numbers oi Flabellum variabile were dredged 

 by us in the Arafura Sea a considerable number^ 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 haemoglobin 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 Coelenterates, 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 Holothuria 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 



' It even became a question whether the majority of specimens were not 

 unpigmented, in which case the exhibition of pigment or chromatism — as it 

 might be termed, in antithesis to albinism — would become the exceptional 

 yariatiou la the species instead of the rule. 



