DR, C. A. MAC MUNN ON THE CHROMATOLOGY OF ACTINIA. 
655 
Sagartia troglodytes. —The solid tissues of this species—at least in the specimens 
examined by me--are poor in colouring matters. They were mostly a pale flesh 
colour, or yellow-white, or almost white, externally. Internally almost colourless or 
yellowish-white, the tentacles slightly green or almost colourless. A dirty brown 
tint was sometimes present in the circumoral part (externally), and in the same place 
some greenish spots, which on microscopic examination appeared to be due to the 
presence of some foreign substance, but not “yellow cells.” 
In the solid ectoderm a spectrum is detectable which is of great interest, as it 
indicates the presence of a colouring matter which is related to hsemochromogen, and 
in some parts the second band of that pigment can be seen. In the stomach wall 
of some invertebrate animals, e.g., Uraster rubens, Asterias, &c., a similar band or 
bands can be seen. These belong to a histo-hcematin, and I have no doubt that such 
is present in S. troglodytes. I have only shown the single band in spectrum 13, 
Chart III. In the interior portion a feeble band before D is also present. I could not 
see a band in the tentacles or in the brown part of the ectoderm referred to. 
Although the lining of the body cavity was so pale, a solution obtained by digesting 
it in rectified spirit and caustic potash, on the addition of ammonium sulphide, gave 
the bands of reduced hsematin. Traces of the same were found in a similar solution of 
the ectoderm. 
The tentacles on extraction with absolute alcohol yielded only an almost colourless 
solution, showing no bands. 
Sagartia bellis. —Some were yellowish externally, with a greenish zone around the 
mouth (externally); internally, brownish ; the tentacles were quite opaque, and when 
squeezed out between glasses brownish in colour, and under the microscope they were 
found packed with “ yellow cells.” Other specimens were of a dirty yellow, with 
white stripes running from the tentacles to the base, their interior was orange and 
the tentacles dirty green; round the bases of the latter a ring of greenish-brown 
colouring matter was seen, and this was also present in the others. In some, however, 
a pale reddish-yellow zone encircled the Sagartia, 
The first specimens referred to on spectroscopic examination gave in the ectoderm 
some uncertain shading in green, while in a few I saw a narrow band in green like 
that of S. troglodytes, and perhaps a second one. In the lining of the body cavity no 
distinct bands were seen. 
In others the results were the same. In striking contrast to these results was the 
examination of the tentacles, as in every instance they showed a banded spectrum 
reminding of chlorophyll.* This spectrum belongs to the mass of “yellow cells” 
which were confined to the interior of the tentacles, and probably embedded in their 
endodermal linings. This spectrum is shown in spectrum 1, Chart IV. On digesting the 
ectoderm in rectified spirit and caustic potash, a pale yellow solution w^as obtained, 
giving spectrum 2, Chart IV. On treatment with sulphide of ammonium no reduced 
* Or rather cldorofucin. 
4 P 2 
