Cell Structure, Growth and Division in the Antheridia of Polytrichum etc. 131 
Sections were cut, for the most part, 5 microns in thickness. They 
were stained witk Heidenhain’s iron-alum haematoxylin (alone, or com- 
bined with safranin, orange G or Congo red), with Flemming’s triple 
stain (safranin, gentian violet and orange G), or with the latter modified 
by the Substitution of pyoktanin blue for gentian violet. 
Observations. 
In my material, division figures in vegetative cells, though relatively 
infrequent, have been seen in considerable numbers. I shall not discuss 
these figures at present, further than to say that they have been studied 
with some care with reference to the possible appearance of structures 
at the spindle poles, such as will be described for the androgonial divisions. 
An aggregation, often rather dense, of granulär cytoplasm was usually 
seen about each pole. Occasional dark-stained bodies, suggesting those 
regularly found in androgonial mitoses, were observed in the polar regions ; 
but these appearances were neither definite nor constant enough to warrant 
a conjecture as to their nature. No evidence has been found in vegetative 
cells of any such relation between kinoplasmic bodies and spindle forma- 
tion as is evident in the prophases of divisions within the antheridium. 
The Structure and Division of the Androgones. 
The Cytoplasmic structures and spindle formation. 
From the first appearance in the young antheridium of a differentia- 
tion into wall cells and androgones, the latter are distinguished by the 
absence of plastids and starch grains, and by the presence of a rather 
dense reticular cytoplasm. Within the cytoplasm, from the time of the 
formation of the primary androgones until that of the division which 
forms the androcyte mother cells, a distinctly-outlined, dark-staining sub- 
stance appears (see, e. g., Figs. 1 — 24, PI. VI). This substance, for reasons 
which will appear as its behavior is described, particularly in its relation 
to spindle formation, seems without question to fall within Strasburger’s 
(1892) category of kinoplasm, and in what follows it will be referred 
to under that name. It is aggregated at different periods in the develop- 
ment of the antheridium into bodies of various form, whose appearance 
often suggests a comparison with one or another of the many dark-staining 
structures which have been observed in the cytoplasm of plant and animal 
cells. Comparisons of this nature will be discussed later. 
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