in Dictyota dichotoma. 173 
by the closely arranged kinoplasmic radiations, and the 
nucleolus rapidly disappears. 
On the disappearance of the nucleolus numerous granules 
appear in the nucleus, which stain deeply, closely resembling 
the chromatin granules. In the mean time the chromosomes 
increase in size, and it seems reasonable to suppose that the 
nucleolar substance contributes materially to their growth. 
The behaviour of the nucleolus during the second mitosis, as 
will be shown later, seems to strengthen this view. 
The chromosomes when arranged in the equatorial plate 
appear, especially when crowded together, which is often the 
case, as rounded lumps. A careful study in favourable cases 
shows clearly that each chromosome is either in the shape 
of a ring, so contracted as to leave scarcely any central space, 
such, for example, as is known to exist in higher plants 
(Podophyllum and Helleborus)^ when each segment or daughter 
chromosome forms one-half of the ring, or it may be in the 
form of a short thick U (Figs. 5 and 6). Sixteen chromo¬ 
somes, the reduced number, are present in the first mitosis. 
To this part of the problem I shall return in a later 
paragraph. 
While on the way to the poles the daughter chromosomes 
sometimes fuse with one another to form large masses ; this 
is especially so in the second mitosis. In the construction of 
the daughter nuclei one or more larger masses of chromatin 
are formed by the chromosomes, a nucleolus appears near 
the chromatin mass or masses, and a nuclear membrane is 
laid down (Fig. 8). The membrane is unquestionably formed 
through the agency of the kinoplasmic fibres. The centro- 
some increases in size and the polar radiations are more 
distinct than in the spindle stage. The connecting fibres 
usually persist until the nuclear membrane is present, but 
a little later they disappear entirely. The chromatin mass 
gradually becoming less dense, soon disintegrates and the 
daughter nucleus passes into the resting condition (Figs. 9, 10). 
During the reconstruction of the daughter nucleus the 
centrosome divides longitudinally, as it seems, the daughter 
