68 SPERMATOGENESIS AND FECUNDATION OF ZAMIA. 
This would seem to confirm the writer’s statement that the blephar- 
oplast is an organ developed primarily for the transportation of the 
male nucleus, but the discrepancy between the question of fusion of 
cell parts is very noticeable. In Zaméa and Cycas the entire sperma- 
tozoid invariably enters the egg cell and the cytoplasm and ciliferous 
band (blepharoplast) fuse with the cytoplasm of the egg, while the 
nucleus journeys on to the egg nucleus, with which it fuses. A num- 
ber of investigators, the writer has noticed, seem to conclude that 
because the nucleus of the spermatozoid travels on alone and fuses with 
the egg nucleus the nucleus alone is concerned in fecundation. It may 
be that the nucleus is the sole bearer of hereditary tendencies and that 
this is the important part of fecundation. The fact remains, however, 
that in Zamia and Cycas and those cases of fecundation that are best 
known there is a fusion of cells, nucleus with nucleus and cytoplasm 
with cytoplasm, as would be naturally expected. We could hardly 
expect the entire spermatozoid nucleus and cytoplasm to fuse with the 
egg nucleus. It would seem as though the cytoplasmic envelope fig- 
ured by Thom, as left by the spermatozoid in the cytoplasm of the 
egg cellafter the nucleus has escaped, must contain the ciliferous band, 
if, indeed, it is not made up almost entirely of the band. From analogy 
with Zamia and Cycas this would immediately be supposed to be the 
ciliferous band of the spermatozoid, the nucleus having united with the 
egg nucleus and the cytoplasm with the egg cytoplasm. 
In the Gymnosperms, according to Blackman, Murrill, and others, 
it is an entire cell that takes part in the fecundation, but no blepharo- 
plast is here present. Dixon (27) was the first to observe in Pinus 
sylvestris that all four nuclei from the pollen tube—the two generative 
nuclei, the pollen tube nucleus, and the nucleus of the stalk cell— 
passed over into the egg cell in fecundation. Blackman (16) confirmed 
this conclusion in his study of Pinus sylvestris, and further stated that 
‘it can not be doubted that cytoplasm also passes over into the 
oosphere, for each generative nucleus in the pollen tube is clearly 
surrounded by its own layer of cytoplasm, as can be observed in the 
stage when the tube is clearly in contact with the oosphere.” Murrill, 
in his study of Zsuga canadensis (91), claims that the contents of the 
pollen tube ‘‘cast into the egg consists of two sperm cells, the stalk 
cell, the vegetative nucleus, and some protoplasm and starch from 
the tube cavity.” The sperm cells are described as having dense 
cytoplasmic contents and large nucleus. The process of fecundation 
described by Murrill compares exactly with what the writer had pre- 
viously described in Zamia (124) and what Ikeno found in Cycas 
(70). Murrill says: 
It is through the first sperm nucleus that fertilization is accomplished. A short 
time after its entrance into the egg it slips from its cell and moves with accelerated 
velocity toward the egg nucleus, the latter remaining stationary and inactive. 
on Se 
