479 
Nuclear Division in the Hepaticae . 
The daughter-nuclei rapidly divide again, and the axes of 
their spindles lie in different directions, so that when one 
is seen in profile the other is commonly viewed from the pole. 
I am unable to say how the chromosomes originate for the 
second mitosis. The whole process is passed through with 
great rapidity, and I did not, even from a large stock of 
material, secure any stages sufficiently early. But the appear- 
ance of the fully formed chromosomes, when lying on their 
respective spindles, imitates exactly that seen in the first 
mitosis. The presumption then is, that the second karyo- 
kinesis is also heterotype 1 in character, just as is the first. It 
is a matter of some importance to settle this question, and 
I hope to be able to do so when my plants fruit again. The 
heterotype character of the first mitosis is shared by every 
spore-mother-cell in its first karyokinesis, so far as it is 
possible to judge from the figures published by Strasburger 
and others. Moreover it is also characteristic of that division 
in the reproductive tissues of animals in which the nucleus 
comes out of rest with the reduced number of chromosomes. 
Now in animals the subsequent mitoses vary in character, 
and also may exhibit certain interesting and, at present, 
obscure peculiarities ; often the next division, at any rate, 
is heterotype, but it may also be homotype. The divisions in 
the spore-mother-cell of Lilies belong to this latter category; 
the first mitosis is strikingly different, not only from all the 
preceding vegetative divisions, but also from the one which 
follows it within the pollen-mother-cell. The indifference 
manifested in the second mitosis in animals (and probably 
also in Fossombronia when compared with Liliuni) as to 
whether it be heterotype or homotype, is of some theoretical 
interest ; it proves that the apparent transverse division of the 
heterotype chromosome cannot be interpreted as the separa- 
tion of a pair of V-shaped chromosomes which had become 
attached by their free ends to each other. 
1 A term introduced by Flemming to denote the remarkable form of karyokinesis 
met with in the division of the spermatocyte-nuclei of the Salamander. Archiv fur 
Mikrosk. Anat., Bd. XXIX, p. 400 et seq. 
L 1 2 
