144 Lloyd Williams . — Studies in the Dictyotaceae. 
flat disc. Those at the periphery are curved and have the free ends 
directed outwards. Careful countings of polar and other views give from 
twenty-seven to thirty-two chromosomes. The polar radiations and 
centrosomes are not nearly as clear as they are during the early prophase 
stage. 
When the daughter chromosomes are halfway to the poles the nuclear 
membrane is still intact, and the centrosomes are visible at both poles. 
Between the chromatic discs and the poles the cones of fibres are clear 
of granules and the fibres are fine and close set, while the interzonal fibres 
are, as usual, fewer, far coarser, and the space between them invaded by 
granules and fibres. When the chromosomes reach the poles, they form 
two flat discs, the distal one being much greater in diameter than the 
basal. Very often a chromosome lags behind the others and projects 
towards the equator (Fig. 5). The membrane has now disappeared, so 
that the nucleolar fibrillae and globule are excluded from the chromatin 
discs (Figs. 5 and 6). The coarse connecting fibres still remain and the 
distal centrosome and radiations are distinct. Sometimes the basal cen- 
trosome can be made out, but there are no radiations. The lower half of 
the figure projects into the vacuolated region while the upper half is 
imbedded in the denser cytoplasm. 
A membrane now surrounds each of the daughter nuclei, the diameter 
of which is much less than in either the preceding or succeeding stages. 
Instead of lying parallel in a flat disc, the chromosomes now form a tangled 
mass, but they are still distinct and preserve their curved form. In this 
condition it is often easier to estimate their number than during the late 
diaster stage. At this period nothing can be distinguished within the 
nuclear membrane besides the chromosomes. The chromosomes gradually 
fuse so as to form an irregular coil or reticulum with a very few meshes. 
This coil is very much thicker in the tetraspore mother-cell nucleus than it 
is in the sister nucleus. Each thick thread is at least double, the median 
line can frequently be seen to be lighter than the two edges (Fig. 6, upper 
nucleus). The strands of this irregular coil are often swollen at intervals, 
and there may be ten to sixteen of the swellings. Throughout this period 
of partial fusion the membrane of the upper nucleus, on the distal side, 
is very irregular, there being a marked projection towards the centrosome. 
A very faint reticulum now appears in the nucleus, and the condensation of 
the coil proceeds till very often it assumes the form of a thick open ring. 
Ultimately the chromatin mass becomes spherical in form and uniformly 
granular or finely fibrillate in appearance, in fact it is the nucleolus. It 
is worthy of note that of the four mitoses described in this paper this 
is the only one in the telophase of which there is no differentiation of 
nucleolar and chromatin masses. The diameter of the nucleus is now 
much greater, and there is a fine but very faintly staining reticulum. 
