» h. n. moseley. 



Alcyonarians. 



Tubipora. — The red colouring of the corallum of Tubipora 

 absorbs all the spectrum but the red, but shows no bands. 



Heliopora. — The intense blue colouring of Heliopora 

 carulea is soluble in the recent or dried condition of the 

 corallum^ neither in hydrochloric acid, ammonia, caustic 

 potash, nor alcohol. When the corallum is dissolved in 

 hydrochloric acid the blue colouring matter is set free as 

 small flocculent intensely coloured masses, which may be 

 seen under the microscope to be insoluble in concentrated 

 hydrochloric acid. The colouring matter, however, when 

 thus set free is readily soluble in alcohol, and yields an 

 intensely blue solution of the colour of sulphate of copper 

 solution. This solution gives no absorption bands, but 

 simply absorbs most of the red and violet of the spectrum 

 (PI. I, No. 1). On the addition of alkalies to the solution it 

 becomes of a dirty green colour. It regains its blue colour 

 on being again rendered acid with hydrochloric acid. The 

 blue solution when evaporated to dryness leaves a blue amor- 

 phous powder behind. The colouring matter is destroyed by 

 nitric acid. 



ZOANTHARIANS. 



A species oi Anthea, obtained off Bermuda in 31 fathoms, 

 was of a dark red colour. The red colouring matter gave 

 no absorption bands, but yielded the spectrum shown in PI. 

 I, fig. 3. 



Polyperythrin. — A large series of simple stony corals of 

 very different genera and two forms of Actinia), procured 

 mostly from deep water in various localities, and also certain 

 Hydroids, have been found to have a partial or entire deep 

 madder-red coloration, due to the presence of a peculiar 

 colouring matter for which the name "polyperythrin" is 

 proposed. The madder colouring matter yields in the fresh 

 condition a very well-defined spectrum of three absorption 

 bands (PI. I, fig. 3 a), the two less refrangible bands being 

 very dark. One band lies in the green and two at the less 

 refrangible end of the spectrum (PL I, fig. 3 a). The 

 green band is the faintest and disappears first on increase of 

 light transmitted or diminution of the thickness of the film 

 of colouring matter employed. This banded spectrum is 

 yielded by fresh portions of the ectoderm or any tissues 

 showing the madder coloration. The colouring matter is 

 very stable, and portions of tissues containing it when dried 

 on a glass slide yield the S2:)ectrum in full intensity after a 

 lapse of three years. The colouring matter is insoluble in 



