1900 | DEVELOPMENT OF THE EMBRYO-SAC 41 
From the material at hand it appears that a short time after 
the last division in the axial row, the primary nucleus of the 
embryo-sac, 7. ¢., of the lower cell, divides, and one of the 
daughter nuclei passes to each end of the already much elon- 
gated cavity. The spindles representing the latter division were 
not obtained, but several cases were found where there were two 
nuclei at each end of the embryo-sac, and still others where 
there were four (fig. 34). One or two sections showed the three 
antipodals, two synergids, and the egg; while near the center of 
the cavity was a very large nucleus, apparently the definitive 
nucleus of the embryo-sac. The fusion of the polar nuclei was 
therefore not observed, but probably took place as indicated by the 
two nucleoli and cross line in fig. 35. Just previous to fertiliza- 
tion the egg-apparatus was found to be separated from the main 
cavity by a delicate membranous wall, and to consist of two 
very small partially disintegrated synergids located very near the 
micropyle, and-a much larger egg nucleus suspended some dis- 
tance below, as in fig. 35. At this stage the antipodals are often 
in an advanced stage of disintegration, and are more or less 
clearly separated by a delicate membrane from the cavity 
above. 
Canna differs from Convallaria, therefore, principally in the 
embryo-sac being formed from one cell of the axial row, and one 
element of the division into four of the mother nucleus. In the 
latter plant the whole axial row and all four elements of the 
division of the mother cell go to form the embryo-sac, 
THE NUCLEAR DEVELOPMENT. 
At a very early stage the nucleus of the archesporial cell 
passes into the condition of synapsis, in which as usual the linin 
is massed together at one side of the nuclear cavity. After a 
‘time indications are seen of the gradual loosening of the knot, 
with a simultaneous migration of the spiral coils to the more dis- 
tant parts of the nucleus. The nucleolus here, as in Convallaria, 
is seen to remain intact during the whole process. It stains 
much deeper with the gentian-violet than does the chromatin, 
