94 BOTANICAL GAZETTE [avers 
second division of the chloroplast follows so closely after th 
first that the final products are arranged for a short time inthe 
form of a bow around the nucleus (fig. 9). Such conditions 
are however only transitory and result from the elongated form 
of such cells. 
The structure of the four daughter chloroplasts exhibits this 
difference from that of the mother structure shown in figs. 44 
The protoplasmic material that formerly filled the spaces betwee 
the starch grains as a spongy network of strands and films nor 
appears to be entirely absent or present only in a much reduce! 
form. The chloroplast has the structure of a vesicle filled with 
starch grains. Itis interesting to contrast this condition with the 
conditions exhibited in the youngest spore-mother-cells. Ther 
the bulk of the chloroplast was made of protoplasm and the fer 
starch grains were insignificant. But in the oldest spore-mothet 
cells the chloroplast has become one great storage vesicle 0 
starch, conspicuous by the absence of that protoplasmic differet 
tiation which is so characteristic of the chloroplast whereve! 
found, 
The problem of the division of the chloroplast and the dis 
tribution of the resultant daughter plastids through the cell 8 
full of interest. Does the development of the furrow and the 
final fission of the chloroplast result from the activity o the 
protoplasm in or around the structure? It is conceivable 
the division has its cause merely in the advantage that mgr 
come from a more even distribution of the chlorophyll throug? 
the cytoplasm. Thus it is obvious that the arrangement show 
in fig. 5 is very unsymmetrical. Perhaps a strain may be exerted 
upon a chloroplast bent around the nucleus in such a mane 
and finally result in its fission, and then lead to a redistributio® 
of the cell contents to bring about a certain balance in thee 
The difficulty of this view as applied to Anthoceros lies 10 * 
- fact that the number of chloroplasts is fixed at four, corresp : 
ing exactly to the number of spores. How could a nume 
coincidence so important in phylogeny be left to the play o 
forces merely acting for symmetry and the advantage : 
