466 Sargant . — The Formation of the 
previous karyokinesis so frequently do. The diaster segments 
are commonly hooked, but occasionally a V-shape is found 
(x, Fig. 3 t). The reconstruction of the daughter-nuclei goes 
on in the same way as after the first karyokinesis (cf. 
Fig. 33 with Fig. 25). The pairs of nuclei may differ 
greatly in size (Fig. 32) or be nearly equal (Fig. 33). This 
seems to depend somewhat on the size of the embryo-sac. 
When it is comparatively long at the time the second 
karyokinesis takes place, the two dividing nuclei are widely 
separated, and the micropylar nucleus is commonly much 
smaller than the chalazal one. This difference is shown most 
clearly during the later stages of division. By the time the 
daughter nuclei have reached the resting-stage they are 
already differentiated in pairs. The two egg-shaped nuclei 
at the micropylar end are cut off from the larger flattened 
chalazal nuclei by the formation of vacuoles as the embryo- 
sac lengthens, and no further change takes place before the 
third karyokinesis (cf. Fig. 37). In short embryo-sacs the 
two dividing nuclei are often of equal size (Fig, 33), and 
the four resting nuclei are similar and placed at nearly equal 
intervals from each other (Fig. 34). The increase in length of 
the embryo-sac then takes place later. 
In such embryo-sacs as these I have found some curious 
stages before differentiation of the nuclei in pairs. They are 
too numerous to be treated as pathological. The four similar 
nuclei are found in all the early stages of division (Figs. 35, 
36), but they never reach the stage of regular spindle forma- 
tion, though I have twice seen indications of spindle-fibres 
surrounding the well-differentiated naked spirem. These 
spirem figures are always arranged in the same way within 
the embryo-sac — a single nucleus near the micropyle and 
a group of three at the chalazal end. I have never found 
embryo-sacs with eight nuclei in the neighbourhood of these 
ovules, and do not believe that the division thus indicated 
comes to anything. As serial sections from older ovaries 
show no abortive or unhealthy ovules, I suppose that the 
four nuclei after making this false start return to the resting- 
