Cytology and Movements of the Cyanophycee. 257 
clusions concerning Spirogyra were based upon very faulty 
and insufficient observations of that organism. 
Zukal (100), working on Tolypothrix lanata, concluded 
that the structures which Wille (85) termed “nucleoli” 
were in reality a number of small cell nuclei, each sur- 
rounded by a portion of cytoplasm, having arisen endo- 
genously by division of the cell nucleus, but having no wall. 
There might be as many as sixty-four of these present, all 
connected by a network with the central body. These he 
termed the nuclei, founding his conclusions on their power 
to divide. He cited, however, his difficulty in getting con- 
stant results, but this, as has been pointed out above, should 
scarcely be considered seriously, except that care must be 
taken, by the use of several reagents, as there suggested, to 
avoid the formation of artifacts. In a later work (99) 
Zukal again called attention to these granules, which he 
now identified with the “red granules” of Biitschli. They 
stained very lightly with safranin, eosin or hematoxylin, but 
hot methyl blue brought them out very strongly. They did 
not really disappear when treated with 5 per cent. potassium 
hydrate, chloral hydrate or 1 per cent. hydrochloric acid, but 
swelled more or less and seemed to disappear. He concluded 
that the granules were coagulated albumen, which formed 
the cell nuclei and surrounded the central clear mass of cyto- 
plasm. He did not enter minutely into the question of cell 
division or of the nucleus, but his conclusions on this point 
were as follows: “In each cell nucleus two nucleoli are 
formed after each simple (amitotic) division. This occurs 
mostly at night. The division of the nuclei (‘red granules’ 
of Butschli) may proceed without the division of the cell.” 
In regard to the chromatophore, his definition was, “‘a defi- 
nite, demarcated part of the protoplasm, saturated with the 
characteristic coloring matter of the plant.’’ He considered 
such a chromatophore, formed of an exceedingly delicate 
reticulum of fine granules, to be present surrounding the 
colorless cytoplasm of the Cyanophycez. Still later Zukal 
