Nuclear Division in the Hepaticae. 497 
abundant at this stage in the cytoplasm about the spindle. 
The appearance of these granules, and their relation with 
the spindle-fibres is such as to lend support to Strasburger’s 
view of the nutritive relation of the nucleolus to the cell-plate. 
Sometimes, however, the process is not so regular, as regards 
the behaviour of the chromosomes, and this especially applies 
to the mode of fission of these bodies. If they split through 
their middle portions, but not quite out to the ends, a com- 
plicated figure may result, and if further, the limbs of the 
V-shaped chromosome become closely approximated instead 
of widely separated, the same appearance met with in Pellia 
is produced. The apices of each half of the V (which 
may be regarded as split in the plane of this paper) then 
diverge towards their respective poles, whilst the ends of the 
two limbs are as yet undivided. It is obvious that in this 
way a figure may be produced which is essentially similar to 
the normal splitting of a heterotype ring, though the events 
which have preceded this particular state differ widely in the 
two cases. But it is of interest to note that this delayed fission 
(so to speak) may occasionally occur in Fegatella , whereas it 
is the ordinary event in Pellia. 
It is remarkable that at the aster stage the radiations 
around the centrospheres die away completely for a time 1 , 
and the centrosphere can no longer be readily distinguished. 
But just before, and during, the migration of the daughter- 
chromosomes to the poles, the radiations again become 
perfectly distinct. It is well known that the duration of the 
aster stage is relatively of considerable length, and thus 
perhaps a condition of comparative repose is temporarily 
established ; this is, however, again broken during the final 
movements of the daughter-chromosomes to the poles, and it 
may be that the reappearance of the radiations, which certainly 
often extend to the periphery of the cell, is directly connected 
with this renewed activity, and renewed necessity for fixing 
the position of the poles. After the chromosomes have 
arrived at their destination, the daughter-nuclei become 
1 See also Pellia epiphylla for a similar occurrence (Farmer and Reeves, loc. cit.) 
