Cytology and Movements of the Cyanophycee. 299 
ing towards a karyokinetic stage, but that in some cells it 
does not reach as advanced a condition as in others. 
In those cells where the spireme segments or chromo- 
somes are formed, each segment or chromosome seems to 
act independently, though all divide at the same time. 
When the daughter chromosomes separate, each retreats 
to its end of the spindle and there begins to diffuse, there 
being as many such centers of diffusion as there are chro- 
mosomes. These centres gradually merge together and 
form the granular nucleus out of which is to form the next 
net-spireme of the next division, or the chromatin vesicles 
of the resting stage. 
(4) ProtTopLasmic CONTINUITY. 
The Cyanophycez have usually been looked upon as com- 
posed of groups of cells, but with no connected organiza- 
tion. As will be seen by the review of the literature, some 
investigators have been able to find pores in the division 
walls of these organisms, through which delicate strands of 
protoplasm passed connecting one protoplast with the other. 
To Borzi is due the credit of having developed this fact to 
the greatest extent. He found that the protoplasts were 
usually connected by means of these protoplasmic threads, 
but that the heterocysts, which showed the most evident 
openings were connected to the other cells by means of 
cyanophycin threads. This protoplasmic continuity between 
the cells, Borzi concluded, assisted the plant to correlate its 
movements. This is certainly a logical conclusion, and one 
that is supported by observation. The evident passage of 
material from which to form the spores, from cell to cell 
through these openings, is still stronger evidence of the 
concentrated organization’ of these plants. Macfarlane 
(51) considered that in the higher plants, sex-forming 
products might pass through these pores from cell to cell 
and thus correlate and epitomize the hereditary substance. 
Gardiner held that ferments and soluble materials passed 
