264 Phillips on a Comparative Study of the 
resembling one in the Cyanophycee. Division was direct, 
the central body first showing the effects of the process. 
When a large spherule of chromatin-like substance was 
present, it might pass into one daughter cell or it might be 
mechanically divided between the two daughter cells. It 
seems that some, at least, of Macallum’s conclusions are 
scarcely warranted by his experiments. He found that there 
was a chromatin-like substance present, still he denied the 
presence of anything resembling a nucleus. Were we to 
take the predominance of authority to determine a definition 
of nucleus, we must let nuclein or nucleus stand as fairly 
synonymous with chromatin. Where one is found, the 
other is indicated, at least indirectly. Macallum’s error, like 
that of many others, seems to be in the mistaken idea that 
a nucleus must be a definitely bounded body. 
Strasburger (76) claimed that there were special cells, 
no longer capable of division, in which several nuclei had 
been formed by fragmentation. The cell nucleus was sur- 
rounded by a colored peripheral layer or chromatophore 
in which cyanophycin grains were found. The function of 
these grains was unknown. Mucous globules were also dis- 
posed in the vicinity of the nucleus, and vacuoles were occa- 
sionally present. The cell wall was composed of cellulose, 
often distinctly stratified, and its outer layer might undergo 
mucilaginization. Multiplication was effected in a vege- 
tative manner, e. g., in the Oscillariacee, by the rounding 
off of two adjacent cells to form a germinal segment. The 
whole filament might break up into short hormogonia, each 
of which then grew out into a long filament. He accepted 
Hegler’s conclusions of a mitotically dividing nucleus. 
Bornet and Flahault (4) considered that the sheath of the 
Cyanophycee received the color which it often possessed 
through the action of light and air. Working upon Tolypo- 
thrix lanata, they were unable to discover anything akin 
to a nucleus. Bornet (3) investigated also the structure 
of the cells of Nostoc in lichens, and noted that their con- 
