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MONTGOMERY. 
[Vol. XV. 
(’89, follicle cells of Blatta)\ de Bruyne (’97, follicle cells of 
Nepa , Periplaneta , Meconema, Aeschnd). E. B. Wilson (’96), 
in speaking of amitosis, states : “ In many cases, however, 
no preliminary fission of the nucleolus occurs ; and Remak’s 
scheme must therefore be regarded as one of the rarest forms 
of cell division.” But the list of cases which I have given 
shows that such cases of nucleolar division are frequent in 
amitosis, so that I conclude that a fission of the nucleolus, if 
not exactly typical for this mode of nuclear division, is never¬ 
theless well represented and occurs here much more frequently 
than in mitosis. Dr. E. G. Conklin has demonstrated to me 
preparations of nucleolar division in follicle cells of Gryllus , 
which he has kindly allowed me to mention here. 
2 . Mitosis. — In karyokinesis the nucleolus may either not 
disappear, or, and this is the most usual case, it disappears 
before the spindle is formed. These two modes may be con¬ 
sidered in turn. 
(a) The nucleolus does not disappear. — In some few cases 
the nucleolus wanders out into the cytoplasm after the disap¬ 
pearance of the nuclear membrane and may remain there for 
some time without undergoing any change. Such cases have 
been described by Hacker (’92a, egg of Aequorea ), Wheeler (’95, 
that of Myzostoma ), H. V. Wilson (’94, ova of Tedamione and 
Hircinia), Tangl (’82, flower buds of Hemerocallis ), Gjurasin 
(’93, Peziza ), and Karsten (’93, sporangia of Psilotum). In all 
these cases the nucleolus ultimately disappears in the cytoplasm, 
though in Aequorea it may be observed still in the cell body of 
one of the blastomeres at the thirty-two cell stage, and the 
daughter-nuclei produce their own nucleoli. (Similar are the 
observations of Mead, ’95; Hacker, ’96, ’97; Rosen, ’95; Zimmer- 
mann, ’96; Metzner, ’94; Foot ’94; Poirault and Raciborski,’96.) 
In the other cases where the nucleolus does not disappear it 
remains within the nucleus. In some of these cases it appears 
to divide into two or more parts; in other cases it may be that 
one of the daughter-nuclei receives the whole parent-nucleolus, 
while in the other one a new nucleolus is produced. There are 
a few observations which show that it sometimes divides ; thus 
Strasburger (’82b, embryo sac of Galanthus) and Rosen (’92b, 
