300 
THALLOPHYTES. 
(C, I), the lower of which remains short, while the upper grows into a flask-shaped cell 
(Fig. 200, D, f, and Fig. 201,/). 
The globular mother-cell of the antheridium (Fig. 200, J, a) first of all divides into 
two hemispheres by a vertical wall passing through the axis of the leaf ; each of these 
is divided into two segments by a vertical wall at right angles to the first ; in each of the 
four quadrants a third division takes place hori- 
zontally and at right angles to the two last walls ; 
and the antheridium now consists of four lower 
and four upper octants of a sphere. Contrac- 
tion by glycerine clearly shows that each of 
these divisions of the protoplasmic body is com- 
pletely effected before the appearance of the 
cellulose-wali (Fig. 200, B) ; the second division 
even takes place before the wall has arisen 
between the two first-formed halves; and the 
four quadrants may be made to contract without 
any wall being visible between them. In Fig. 
200, jB, the third division has also taken place, 
the second vertical wall is already formed, and 
the two quadrants there visible are already 
divided ; but no horizontal wall has yet appeared. 
In Fig. 200, A, a, are shown the eight octants 
in perspective together with their nuclei. Each 
octant now breaks up first of all into an outer 
and an inner cell (Fig. 200, C) ; the latter is 
again divided in all the eight octants {D), so 
that each octant now consists of an inner, 
a middle, and an outer cell {D, i, m, e). Up 
to this time the globe remains solid, and all 
the cells lie close to one another ; but now 
commences an unequal growth, and with this 
the formation of intercellular spaces (Fig. 201). The eight outer cells {e) are the young 
shields, the side-walls of which show even at an earlier period the radial infolding 
already mentioned; they grow more strongly in a tangential direction than the inner 
Fig. 201.— Antheridium of Nitella flexilis in a further 
stage of development (X about 500), 
