270 Phillips on a Comparative Study of the 
withstanding chemical reagents, and therefore resemble the 
cutin of the higher plants, but in chemical and optical 
characters have no relation whatever to it. (3) The walls 
of the heterocysts, on the other hand, consist wholly of 
cellulose. (4) A substance which has the nature of pectine 
(staining with ruthenium red) is concerned in the forma- 
tion of the gelatine slime coverings. (5) The protoplast 
is divided into a peripheral layer carrying the coloring 
matter and a central colorless portion. A colorless hyalo- 
plasm layer usually surrounds the peripheral portion of the 
protoplast under the cell wall, and a similar layer usually 
separates it from the central body. (6) Many granules 
containing the coloring matter are packed into the periph- 
eral protoplasm, giving it the appearance of a homo- 
geneous layer, which, however, by the use of concentrated 
magnesium sulphate solution and Zeiss’ apochromatic 
lenses, may be easily resolved into its constituent granules. 
These granules contain the chlorophyll and phycocyanin 
blended together in one and the same coloring body, so that 
we have an association of coloring matter similar to that 
found in the Rhodophycee (54). (7) These granules 
which carry the coloring matter are regarded as the chroma- 
tophores and are therefore designated as ‘“Cyanoplasts.” 
They are connected by fine protoplasmic threads with the 
peripheral protoplasm and with a pocket-like layer of proto- 
plasm surrounding the nucleus similar to the pellicle sur- 
rounding the nucleus of Spirogyra. (8) Starch or any 
starch-like substance is lacking in the Cyanophycez, but gly- 
cogen is present, which is the first assimilation product of 
these plants, because it appears and disappears according as 
the plant is grown in light or darkness. (9) Beside the 
cyanoplasts, the peripheral cytoplasm contains two other 
enclosures, the albuminous crystalloids (cyanophycin granules 
of other writers), and the slime vacuoles (slime balls of other 
authors). These enclosures are always found in the peri- 
pheral protoplasm of the cell. (10) The albuminous crystal- 
