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chromatophores, where there is naturally more room for them. 
They rarely occur in the extreme peripheral lining layer of 
protoplasm, and are usually confined within the outermost layer 
of chromatophores. 
It usually happens that the chromatophores stain more 
lightly in Heidenhain’s iron haematoxylin than the colourless 
cytoplasm. The opposite, however, is seen in Fig. 1, K, which 
shows a surface section in which the chromatophores have 
stained more deeply than the protoplasm. The chromatophores 
are differentiated very well by the use of chlor-zinc-iodine (Fig. 1 
N) or fuchsin, in both of which they usually become more deeply 
coloured than the intervening protoplasm. 
The chromatophores w’ere usually so numerous that the whole 
of the cell-cavity was completely filled, and only very occasionally 
were vacuoles present as seen in Fig. 1, L and I. 
The nuclei in Ch. Ncegelii are often very numerous, but 
vary very much in number according to the size of the individual 
(Fig. 1, C-G). In some of the larger cells the number of nuclei 
present must often be more than sixty, but they are very difficult 
to count in entire specimens because of the thickness of the cell, 
Fig. 2. Characiopsis saccata sp. n. A-G, various living individuals, E being 
the most usual form, x 610 ; H-L, stained specimens showing the varying 
numbers of nuclei x 610 ; M and N, stained specimens showing chroma¬ 
tophores and nuclei x 1720 ; O. transverse section x 1720 ; P.showing probable 
formation of zoogonidia x 1720, 
