(419) 
the equator between the connecting threads. Hence the daughter- 
nuclei are finally separated from each other by granular protoplasm 
with adventitious vacuoles of the embryo-sac. Now, when later the 
parietal layer of protoplasm divides into cells, the large embryo-sac 
vacuole does not partake in this process, but each newly formed 
endosperm-cell is provided with a certain number of adventitious 
vacuoles. 
So there is a certain antithesis here with what happens in ordinary 
cell-divisions in young cells, but with the vacuole theory of bn Vrins 
and Went this process also is in complete harmony, for Want has 
shown that small adventitious vacuoles can occur in large numbers 
in all sorts of ordinary cells and can in all respects be compared 
with the large vacuole, from which they can also be produced 
by division. I should not he surprised if further investigation 
showed that their occurrence is much more general still than is now 
supposed. 
The case met with in the embryo-sac of Mritillaria and many 
other plants stands by no means isolated, and is also met with in 
the division of other multinuclear cells. Werr mentions some cases 
of this kind in his investigation about the vacuoles of Algae. 
(Chaetomorpha aerea, Acetabularia mediterranea, Codium tomentosum). 
I had an opportunity personally to observe a similar case of 
division in the formation of asexual zoospores in the cells of Hydro- 
dictyon utriculatum. While the zoospores, which had been formed by 
division of the parietal layer of protoplasm, were partly in motion and 
partly had already arranged themselves to a network, all this inside 
the wall of the large mother-cell, L saw the middle part of this 
cell occupied by three great tonoplast vesicles, having their origin 
in the great central vacuole of the cell and which, upon being 
heated under the microscope, first shrank and then burst. Hence 
here, no more than in the embryo-sac of Fritti/laria, the great 
central vacuole took part in the formation of new cells. That the 
zoospores were provided with very small vacuoles, present in the 
granular protoplasm, cannot be doubted according to the above- 
mentioned investigations of Went. I also observed them very distinctly 
in the cells of the young nets very soon after their formation. 
Finally it requires to be mentioned that the doctoral dissertation 
of Mr. Sypkens will soon appear in a German translation in the 
second Part of Volume I of the Recueil des travaux botaniques 
Neerlandais. 
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