DR, C. A. MAC MUNN ON THE CHROMATOLOGY OF ACTINIA. 
651 
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 be 
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 Btcnodes 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 hsemochromogen, 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 actiniohsematin. But this I hope to 
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 
v.'ere 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 I), 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 -g-gbiflli inch in diameter, others tli; they were mostly Wo 
