Observations on the chromatology of Actiniae / by C.A. Mac Munn.

  • MacMunn, Charles Alexander, 1852-1911.
Date:
1885
Catalogue details

Licence: Public Domain Mark

Credit: Observations on the chromatology of Actiniae / by C.A. Mac Munn. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    the chlorophyll-like pigment. On microscopic examination the tentacles were found packed with “ yellow cells,” lodged in part in their endodermal lining. They differed in no respect from the “ yellow cells ” of Sagartia bellis and Anthea cereus, to he described further on.* Schulze’s fluid developed a distinct cellulose reaction in their outer wall, and evidence of starch was obtained by treatment with iodine in iodide of potassium, especially after maceration for some time in a weak solution of caustic potash and neutralizing with acetic acid (Geddes). Further, it would seem that these “ yellow cells ” had taken the place of the red colouring matter of other species, to a great extent, since the latter was present in mere traces. On examining the small variety of Bunodes ballii from the same locality no “ yellow cells ” could be detected in the tentacles or elsewhere. Their tentacles were mostly coloured pink in the inner row, and colourless in the outer row, and the former gave a well-marked actiniochrome-like spectrum, spectrum 17, Chart II. The ectoderm was in places lake-red (and the base dotted with red), and gave spectrum 18, Chart II. This spectrum, on comparison with the tentacles, shows the presence of a band near the violet, while the other band is well marked. In some specimens the lining of the body cavity (endoderm) was pink, and in such cases gave spectrum 1, Chart III. ; the second band of which is remarkably dark, in other cases it was brownish-yellow, and gave no well-marked band. I failed to procure haemochromogen, however, from these anemones, which is very remarkable. Digestion of the different parts in rectified spirit and caustic potash gave a negative result after repeated trials. Still the fact is interesting that the colouring matter of the ectoderm resembles, with regard to the first band of its spectrum, that of Actinia mesembryanthemum. It may have been a pigment which is intermediate between actiniochrome and actiniohaematin. But this I hope lo decide when 1 have an opportunity. The replacement of this pigment by the colouring matter of the “ yellow cells ” in the large variety is of great interest, and teaches that the presence of the colouring matter has something to do with the absence of “ yellow cells ” in the small variety. It would be premature to say that this pigment is peculiar to the small variety, but it may possibly be a special one like that of Sagartia parasitica. Sagartia dianthus.—Specimens of this Actinia were procured from Weymouth. Some were yellow-brown externally, others white. The tentacles generally flesh-coloured; the lining of the body cavity generally reddish. The ectoderm of the yellow-brown specimens showed a very badly marked band before D, and a feeble shading in green, which recalled to mind the spectrum of brown specimens of Actinia mesembryanthemum; the ectoderm of white specimens showed no band. The endodermal parts showed only a faint shading in green ; and all these spectra were too indistinct to be mapped. In a small orange coloured Sagartia dianthus a bit of ectoderm and the orange brown-red endodermal parts gave spectrum 2, Chart III. * These yellow cells measured 2-qVo^ inch in diameter, others -goWth; they were mostly -gWgth.