io8 
Notes . 
When the four nuclei show signs of approaching division, the 
appearance of the lowest one is very different from that of the upper 
three. In these the coiled chromatic ribbon which marks the spirem- 
(or knauel-) stage is beautifully differentiated, while the lowest (chalazal) 
nucleus still has the reticulated appearance of the resting stage. Later 
on each of the micropylar nuclei has formed a small spindle and the 
upper chalazal nucleus a larger one, while the lower chalazal nucleus 
has divided in such a way that each segment appears as a hemi- 
spherical reticulated shell. These shells are connected by numerous 
fibrils, apparently formed by the stretching of the network in the 
equatorial region of the mother-nucleus. The division of the lower 
chalazal nucleus is complete before the three karyokinetic figures have 
passed out of the nuclear-plate-stage. The daughter-nuclei of course 
appear in the resting stage, and are connected by numerous fine threads 
which represent fairly enough the usual ‘ connecting threads ’ of the 
later karyokinetic stages. Indeed the whole appearance of this lowest 
pair of nuclei is now that of a rather poorly preserved di-spirem figure. 
The three spindles which occupy the rest of the embryo-sac are typical 
examples of karyokinetic figures, and form a curious contrast to the 
ill-defined appearance presented at the chalazal end. 
I cannot do more here than allude to the possible theoretical 
importance of this distinction between the formation of the two 
lowest antipodal nuclei and that of the other six nuclei which are 
found in the embryo-sac before fertilization. So far as it goes, it tends 
to confirm Weismann's view that the elaborate mechanism of karyo- 
kinesis provides for the transmission of hereditary qualities. I hope 
to discuss the question at length when the details of my work are 
published. 
ETHEL SARGANT. 
