264 
Rudolf Beer. 
another, but at certain points their soft semi-fluid substance appears 
to remain adherent, and branches or connecting arms are drawn out 
between them at these spots. As the nuclear cavity enlarges and 
the chromosomes become more and more widely separated from 
one another, the branches between them become proportionally 
longer, and gradually the substance of the chromosomes appears to 
be lost in the series of reticulations which are in this manner spun 
out. 
From what has been said it will be seen that there is a complete 
reconstruction of the daughter-nuclei at the conclusion of the first 
meiotic division. The second division calls for no special notice in 
this brief communication. It may be mentioned here that I can find 
no evidence of the degeneration of sporogenous tissue sufficient to 
possess any theoretical significance. It is true that in a few 
sections one or perhaps two degenerating cells could occasionally 
be found, but I am inclined to attribute their occurrence to 
peculiarities in the penetration of the fixing agent, and I do not 
consider that any importance can be attached to them 1 . At the 
conclusion of the second meiotic division the spore-tetrads are 
completely separated from one another and are enveloped in the 
massive tapetal plasmodium. 
The young spores (or pollen-grains) of the majority of plants 
which have hitherto been examined are enclosed in temporary walls, 
often of a mucilaginous nature, which the older botanists called 
the “special-mother-cell wall,” and which Strasburger has more 
accurately and concisely named the “ special-walls.” 
Although the plasma-membrane limiting the spores of Equisetum 
often stains rather deeply, and to some extent simulates a cell-wall, 
I have come to the conclusion, after a very careful examination of 
my preparations, that no special-wall is developed in this plant. 
This fact is of some interest because several other instances 
occur in which a very massive tapetal plasmodium is associated with 
the feeble development or entire absence of the special walls. The 
Ophioglossaceze furnish excellent examples of this relation between 
the two structures. Arum maculatum, among pollen-bearing plants, 
is another instance of the association of an exceptionally massive 
tapetal plasmodium with comparatively feebly developed special- 
walls. In those plants, on the other hand, in which a secretion- 
1 I have seen nothing to compare with the extensive degeneration 
of sporogenous tissue described by Professor Bower in 
Equisetum. I will, however, discuss this matter more fully in a 
future communication when illustrations will be given. 
