Allen—Spermatogenesis and Apogamy in Ferns . 17 
•ure 16). The bulk of the cytoplasm lies hack of the middle 
of the spiral and bulges out beyond the posterior coil of the 
nucleus (to the right in figure seventeen and to the left in figure 
eighteen). 
Figure nineteen shows a longitudinal section through the cell 
somewhat above the median plane at a stage when the nucleus 
forms about two turns of a spiral. Four portions of the coil 
appear at a, b, c and d respectively. The anterior end is below. 
Figure twenty shows the coil with its posterior end uppermost. 
The anterior part which would lie under the portion drawn, is 
not represented. 
From these drawings (drawn to the same scale as those pre¬ 
ceding) it is seen that a marked contraction has taken place in 
both nucleus and cytoplasm. The larger nuclear coil has only 
three-fourths its former diameter. The hollow of the same 
coil, however, is as large as before. This decrease in the vol¬ 
ume of the nucleus is accompanied by a contraction of tbe 
chromatin network into a coarse reticulum containing heavy 
aggregations of chromatin irregularly connected. 
The blepharoplast bears the same relation to the nucleus as 
before. 
The cytoplasm has undergone an even greater alteration than 
the nucleus. The cytoplasmic mass has no longer a bulging con¬ 
vex outline. At the posterior end (figure 20) the cytoplasm 
has drawn back into the hollow of the spiral. At the anterior 
end also there are changes. The shrinking in of the cytoplasm 
and the pushing forward of the anterior end have continued. 
The mother cell wall, already vague and somewhat disinte¬ 
grated in the preceding stages, is here nearly obliterated, and 
the intercellular slime is encroaching upon the space between 
it and the developing antherozoid. The cell wall is omitted in 
later drawings. 
The further development consists "in the condensation of the 
chromatin into an apparently homogeneous mass and the elon¬ 
gation of the antherozoid to form a rapidly narrowing spiral 
about which the cytoplasm shrinks to form a close fitting sheath. 
A stage in this process in which the nucleus forms between 
two and one-half and three coils, is shown in figure twenty-one 
2 
