Cytology and Movements of the Cyanophycee. 291 
crust to function as a chromatophore, though not exactly 
deserving that name, while Hieronymus considered this 
crust not only to function as such, but to be rightly so called. 
Chodat was unable to distinguish between central body and 
crust layer and consequently, with Deinega, considered that 
no special color-bearing organ was present. Zukal defined 
the chromatophore as any “portion of protoplasm which 
contained the coloring pigment.” In general this seems to 
be a proper definition, though in its broad sense it would 
include the whole of the cytoplasm. In the Cyanophycee 
which serve for the basis of this investigation, the two pig- 
ments, chlorophyll and phycocyan, are dissolved in the outer 
protoplasmic zone of the cell, coloring the greater portion 
of it. Surrounding this zone is a delicate colorless proto- 
plasmic layer separating it from the cell wall. The colored 
zone has no definite structure other than that of the pro- 
toplasm and the cyanophycin granules which it contains. 
In the sense of Zukal’s definition, then, the colored zone 
would rightfully be termed a chromatophore, and it cer- 
tainly functions as such, though it also has to perform the 
functions of the cell cytoplasm as well. This is not to be 
wondered at, for in primitive organisms like these, one 
would expect to find an overlapping of functions which will 
later be differentiated and performed by separate organs. 
Hegler (38) brought together in tabular form the views 
generally held concerning the form which the coloring mat- 
ter takes. It is here reproduced with a few additions. 
I.—Pigment completely diffused in the protoplasm; Nae- 
geli, Schmitz, Zacharias and the text-books. 
I].—Pigment embedded within the walls of a web struc- 
ture of the crust layer; Palla and Biitschli. 
I1I.—Pigment in net-like plates surrounding the central 
body; Deinega. 
IV.—Green chlorophyll in grains, embedded in a color- 
less fibrillar system; according to Meyer, moreover, the 
grains correspond to the chlorophyll bodies of higher plants 
