Cytology and Movements of the Cyanophycee. 271 
loids are usually crowded into the heterocysts, being at the 
ends where the pore enters, or in the spores, or in the older 
vegetative cells that have ceased to divide. They are entirely 
absent from the young, rapidly dividing cells. Their crystal- 
loid character is attested by their sharp angular outlines. 
Their albuminous character is shown by their chemical and 
staining properties. (11) In cultures grown in the dark, 
these albuminous crystalloids are consumed. They are also 
consumed in the germination of spores. Such facts, together 
with their always being formed where food material is 
accumulating caused Hegler to regard them as reserve ma- 
terials. (12) The slime vacuoles are difficult to distinguish 
from the albuminous crystalloids except by staining reac- 
tions, and their composition cannot be exactly identified. 
Their staining properties, however, caused Hegler to con- 
sider them to be a slime material, very much like albumen, 
similar to that present in Fucus vesiculosus, and many other 
plants. It approaches nearest to mucin. (13) The chemical 
and physical properties of the granular parts enclosed in the 
peripheral protoplasm, together with their incapacity to 
increase by division, and their entire absence in the dividing 
cells indicate that neither of these granules can be consid- 
ered as of a nuclear nature. (14) The principal point in 
the question of the Cyanophycean cell was that of the nature 
and importance of the so-called central colorless body. 
Hegler considered that his investigations had conclusively 
proven that these central bodies were the cell nuclei of the 
Cyanophycez, and that their behavior during division gave 
sufficient grounds on which to base this judgment. (15) 
In all cells of the Cyanophyceze with the exception of the 
heterocysts where the nucleus early degenerated, there was 
a single cell nucleus whose form depended to a great degree 
on the size of the cell. In round cells it was spherical, in 
elongated cells elongated, the long diameters of the cell 
and nucleus being parallel. (16) The resting nucleus con- 
sisted of a slightly stainable foundation mass, in which were 
