GYMNOSPERMS. 157 
being due to a greater need of food material by this part of the central 
cell; for it is here that the greatest activity takes place during the 
maturing of the egg-cell, which culminates in the formation of the 
ventral canal-cell. Webber does not find any protoplasmic connections 
between the egg-cell and those surrounding it in Zamda, and so far 
as the author is aware no such protoplasmic connections exist in the 
higher Gymnosperms. In Cycas the phenomenon described by Ikeno 
is, if true, probably an adaptation to the rapid transfer of nutritive 
material from the surrounding cells to the egg-cell. 
Strasburger (’or, pp. 550-553), in a late publication on the proto- 
plasmic connections between cells in plants, calls into question the 
statement that nuclei or nuclear fragments pass bodily through the pits 
of the surrounding cells into the egg-cell of Gymnosperms as a normal 
phenomenon, and asserts that it is the result of injury due to pressure 
or fixing reagents. 
There seems to be no doubt that in all Gymnosperms in which the 
egg-cells reach such an enormous size the cells immediately surround- 
ing the egg contribute directly to the nutrition of the latter, but it is 
not clear why any of the material should pass over bodily into the 
egg-cell. 
The final step in the development of the archegonium is the forma- 
tion of the ventral canal-cell, which takes place immediately preceding 
fecundation, and consequently this cell persists only a short time (Fig. 
67,A). It was probably due to this fact that the presence of a ventral 
canal-cell was not observed by Warming and Treub. Only a plasma 
membrane and not a cell-wall is formed separating the ventral canal- 
cell from the egg. It is not at all improbable that in some cases a 
plasma membrane may not be formed, and such is reported for Ceph- 
alotaxts fortunt by Arnoldi (1900). The formation of a plasma 
membrane is, however, of secondary importance in the formation of 
the ventral canal-cell, for if the nucleus of the central cell of the 
archegonium divides karyokinetically, and one of the daughter-nuclei 
becomes the functional egg-nucleus, the division is certainly to be 
regarded as the formation of a ventral canal-cell whether a plasma 
membrane is formed or not. 
Botanists have sometimes been inclined to refer to the formation of 
the ventral canal-cell as a maturation process similar to that in the 
animalegg. Ikeno speaks of this step in the development as the period 
of maturation (Reifungsperiode), which recalls the formation of the 
polar bodies in the animal egg, but I do not infer that he considers the 
two processes homologous. He states, however, that it appears prob- 
