378 TRANSACTIONS AND PROCEEDINGS OF [Sess. lvi. 



{m.2').c., fig. 25*) occupies a position beneath the two syner- 

 gidae {Sijn) and the ovum (ov), and how the antipodal prim- 

 ordial cell (a.j^.c, fig. 25*) lies in close contact with and 

 above the three antipodal cells (ant). The cell-plasm of 

 the micropylar cell does not occupy a large portion of the 

 embryo-sac-wall, while the antipodal cell on the right is 

 attached by a broad base to the sac-wall. As the ovule gets 

 older, the cell-plasmata of both primordial cells commence to 

 wander over the inner aspect of the sac (fig. 25**), and thus 

 shut off the vacuole from the sac- wall in the upper and lower 

 portions of the embryo-sac, but as yet the vacuole touches 

 the wall at tlie places (2?. ^?., fig. 25*). In a slightly older 

 ovule (fig. 26^), the cell-plasm of the micropylar cell has 

 commenced to stream over the inner aspect of the sac, and 

 we see, in a mesial section through the same ovule (fig. 26*), 

 how the antipodal cell has also sent out long pointed pro- 

 cesses, how further, two of these processes, one from either 

 end of the eml^ryo-sac, have formed a distinct protoplasmic 

 connection between the two primordial cells (see left side 

 of same figure). Tlius the initial step in the conjugation 

 of the two primordial cells has been brought about ; the 

 movement of the protoplasm reminding one vividly of the 

 formation of pseudopodia in an amoeba, or of the plasraodia 

 in a myxomycete. 



In fig. 27^ the inner aspect of the sac is lined by proto- 

 plasm arranged in a reticulate manner with nodular swellings, 

 while in fig. 27*, representing the next section through the 

 same ovule, the position of the two nuclei of the primordial 

 cells is illustrated ; we see, further, in the same figure that 

 the antipodal cell-plasm has made its way between the true 

 antipodes and the nucellar cells (/). 



The conjugation of the cell-plasmata then becomes very 

 evident along one side of the sac, fig. 28, and the antipodal 

 nucleus (a. n.) begins to travel towards the apical end of the 

 sac, while the micropylar nucleus (m. n.), lying close to the 

 membrane of the egg-cell (or below and between the egg- 

 cell and the synergidje, fig. 27"), remains stationary. The 

 anti{)oil;d nucleus may, in some instances, contiiuie to move 

 along the wall of the sac, V)ut one more comnioidy finds a 

 thick strand of protoplasm detaching itself from the wall and 

 forming a column which joins the antipodes with the syner- 



