276 Reed . — The Nature of the Double Spireme in Allium Cep a. 
due to the fact that they are closely massed together, for it will be noticed 
that the pairing is extremely well seen in the chromosomes which stand out 
from the general tangle. 
Attention should be directed to the chromosomes x of PI. XVIII, 
Figs. 22, 23, and 24, which are quite different in form from the others, and 
may therefore be termed ‘ hooked ’ chromosomes. 
It is whilst the daughter chromosomes are passing to the poles that 
the beginnings of the longitudinal fission are effected. It makes its ap- 
pearance as a series of slits (PI. XVIII, Figs. 22 b } 23, and 24). At this 
stage no lateral attachments between neighbouring chromosomes have been 
effected, so that in this case the split is not due to the lateral attachments 
pulling out the chromosomes, as suggested by Fraser and Snell (6) for 
Vicia. 
Telophase. 
Lateral attachments between neighbouring chromosomes are now 
freely effected (PI. XVIII, Figs. 25, 26, and 27). The free ends of the 
chromosomes are drawn inwards and fusions take place between these free 
ends, the result being that a somewhat flattened nucleus is formed in which 
the chromatin is present as a flattened sphere with rather large spaces in it 
(PI. XVIII, Fig. 26). This is later followed by the expansion of the nucleus 
and the assumption of an oval or rounded form. With the distension 
of the nucleus the slits previously observed in the anaphase naturally 
become much larger, since now all the chromosomes are more or less 
connected one with another and form a hollow sphere. Polar views of 
the nucleus show that the sixteen chromosomes can still be recognized 
(PI. XVIII, Fig. 28), although, as has been pointed out above, fusions take 
place between neighbouring chromosomes. 
At this stage one or more chromatin knots have been formed on some 
part of the chromatin sphere (PI. XVIII, Fig. 28). Each knot later develops 
the characteristic nucleolar vacuole, so that there is little doubt that they 
represent the beginnings of the formation of the nucleoli. 
As the nucleus passes further into the resting stage the amount 
of chromatin diminishes in the nuclear network and increases in the 
nucleolus, the splits in the network open out still further, and finally the 
nucleus consists of the faintly staining fenestrated sphere almost entirely 
devoid of stainable matter. 
During the telophases an enormous number of cross-connexions are 
made between neighbouring chromosomes, so that the boundaries of each 
become difficult to follow. A recognizable foundation for each chromosome 
cannot be seen during the resting stages, such as is suggested by Gregoire 
( 7 ) for Allium , Muller ( 17 ) for Najas marina , and Overton ( 19 ) for Caly- 
canthus , &c. 
