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Wager . — On the Structure and 
simply a very special case of ordinary karyokinetic division 
brought about possibly by the small size of the nucleus.’ 
Finally, Isatschenko (’ 95 ) describes a process of indirect 
nuclear division in the cells of the pileus and stipe of Pholiota 
aurea , Fr., in which the chromatin substance collects at the 
equator of the nucleus and divides into two portions which 
gradually approach the poles of the nucleus, where small 
round bodies (centrosomes ?) can be seen. The nucleus 
becomes constricted in the middle and two daughter-nuclei 
are formed. 
In the process of nuclear division, as shown in the oogonium 
of Cystopus (Fig. 28, 1 to 5), the nucleus first of all loses its 
nucleolus (1) and the network becomes at the same time 
clearly visible and is seen to be granular. Its network then 
appears to be transformed into a number of granular chromo- 
somes (2), which stain reddish, and among which a faintly 
stained blue network is to be seen. The appearance of the 
nucleus at this stage gives one the impression that the chro- 
mosomes are very numerous, but on counting them, as well 
as one is able, there appears to be about 12 or 16. It is 
very difficult to be sure of this however. I have counted 
them in the stages 2, 4, 5 (Fig. 28) and the impression always 
given is that 12 to 16 is the number. 
In 3 (Fig. 28) the nuclear membrane is seen to be slightly 
irregular ; the chromosomes have contracted towards the 
middle, and a blue network is seen surrounding them irregu- 
larly and is also seen between them. Then the nucleus 
begins to elongate in one direction and becomes oval- shaped. 
The chromosomes begin to take up a transverse position to 
form the equatorial plate, and at the same time the nuclear 
spindle appears, and the fact is strongly impressed upon one 
that it is formed out of the faint blue-stained network of the 
nucleus. This is supported by the fact that the nuclear 
membrane remains intact. In 5 (Fig. 28) the equatorial plate 
is seen and a well-formed spindle. The nuclear membrane 
becomes, at this stage, more indistinct and presents a granular 
appearance, which is probably the first indication of its 
