172 ANGIOSPERMS. 
by beautiful systems of kinoplasmic connecting fibers. Cell-plates, or 
plasma membranes, are next formed by the connecting fibers, in a man- 
ner common to the higher plants, by which the three cells of the egg- 
apparatus are differentiated, while a fourth nucleus, the upper polar 
nucleus and a sister of the egg-nucleus, remains free in the cytoplasm 
(Fig. 73, B). In A, Fig. 73, three nuclei of the tetrad are shown. 
The cell-plates are nearly formed, and it is clear that the lower cell to 
the right will become the egg-cell, while the nucleus to the left is 
5 eae. 
Ai 
ESS ALT, 
* 
Fic. 72.—Later stages in development of embryo-sac of Lilium martagon. 
A, the nucleus has divided; the daughter-nuclei aré connected by connecting fibers 
which have shown a tendency to form a cell-plate. 
B, close of second nuclear division; the four nuclei are connected with each other 
and with plasma membrane by kinoplasmic fibers, 
unquestionably the upper polar nucleus. The cytoplasm immediately 
surrounding this nucleus is not delimited by a plasma membrane as in 
the case of the other three cells. In B, Fig. 73, the relation of all 
four nuclei is evident. 
The antipodal cells in Lzlium martagon are formed in the same 
way as those of the egg-apparatus when the process is normal, although 
the development of these cells is not infrequently variable in this 
species (Mottier, 97). Among the Angiosperms in general the anti- 
podal cells represent a very variable group both as to number and 
