Division in Mnium hornnm. 155 
9. On emergence the spireme has become shorter and thicker ; a net* 
work is formed, and soon the second contraction supervenes ; this is 
characterized by the looped arrangement of the spireme, which now exhibits 
traces of longitudinal fission. 
10. The chromosomes are formed by aggregation of the chromatin 
to certain portions of the thread, and in these longitudinal fission can still 
be seen. They are separated by transverse division of the thread. The 
nucleolus passes into the cytoplasm and soon disappears, while the chromo-. 
somes remain in the centre of the cell. 
11. No centrospheres are found at the poles of the spindle. The 
chromosomes, six in number, become arranged on the equatorial plate, and 
show the characteristic O and X forms. They divide transversely and pass 
to the poles. 
12. The homotype division results in the formation of four nuclei, 
which are later found in the spores. 
The investigation was commenced in the Botanical Department of the 
University of Glasgow, and I am greatly indebted to Professor Bower, F.R.S., 
for the facilities which he afforded me. In conclusion, I wish especially to 
express my thanks to Professor Farmer, F.R.S., for his constant help and 
valuable advice during the progress of the research. 
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