284 Phillips on a Comparative Study of the 
ments. Biitschli found that when the Cyanophycee were 
digested in artificial gastric juice the central body floated 
free in the otherwise empty cell and showed a Brownian 
motion. The central body of the resting Cyanophycean cell is 
therefore usually composed of larger or smaller hollow vesi- 
cles of chromatin, as claimed by Lauterborn (47) for Diatoms. 
These vesicles are imbedded in a finely granular ground 
substance, which sends radiating lines toward the periphery, 
piercing the chromatophore. If a cell wall be ruptured and 
the cell contents pressed out, these hollow chromatin vesicles 
may be seen lying isolated within the protoplasm (Fig. 24). 
In cross sections the vesicles are shown to be quite numer- 
ous (Fig. 31) and of a small size in the naturally grown 
plant, but in material grown in the full culture solution they 
are relatively large and few in number (Fig. 30). Radi- 
ating from the central body are seen fine granular kino- 
plasm-like processes of the ground substance, which pierce 
the chromatophore and pass out to the cell wall where 
they form the central portion of protoplasmic ciliary-like 
growths, about one-half to one micron in length on the 
sides of the organism. In Oscillaria there may be as many 
as four such processes shown in optical section on one side 
of the cell, while on the other side only one or two may 
be seen. In Cylindrospermum these ciliary processes are 
more numerous and regularly distributed. 
The central body has no membrane surrounding it. In 
this it is different from the nucleus of higher plants. Hlier- 
onymus has suggested that this condition be termed an 
“open nucleus.” Palla, Strasburger and Fischer described 
a delicate membrane surrounding the central body, but in 
this investigation, nothing of the kind has been found. The 
opinions of various investigators of the Cyanophycee do 
not agree as to the nuclear nature of the central body. 
Zukal did not consider it to be a nucleus, but attributed 
that function to the cyanophycin granules, while he re- 
garded the central body as the cytoplasm. Hieronymus 
