Meiotic Nuclear Divisions of Gallonia caudioaus. 735 
Gradually the individual fragments unite end to end until the typical and 
definite sixteen chromosomes can be identified. 
Once more it is necessary to emphasize the fact that in the archesporial 
nuclei, the chromosome fragments are more or less homogeneous and show 
little sign of longitudinal fission (Fig. 27), whereas in the chromosome 
fragments of the nuclei of the roots (PI. LIX, Fig. 12) the fission is most 
marked. As the chromosomes form, they lie somewhat polarized towards 
the nucleolus. The next stage shows them as definite entities, their sides 
still united by the delicate connexions (Fig. 13) which invariably arise 
from a slight protuberance. The difference in size of the chromosomes is 
most noticeable. In the roots the chromosomes often show bifurcated ends 
and the longitudinal fission throughout their length (Fig. 14), whilst others 
show only partial fission, and others complete chromatic concentration. 
The edges of the longitudinal fission are ragged. As has been already 
mentioned, the cells of the outer layers of the root show an exaggerated 
fission (Fig. 12). In exceptionally precocious cases the chromosomes may 
have split apart, forming the widely extended V’s, even before the cytoplasm 
show's any radiations (Fig. 13, v). As a rule the first signs of the radiations, 
which indicate the line of future stress of the fibres, appear when the 
chromosomes are distributed throughout the nucleus. The fibres push 
themselves into the nucleus, the nuclear wall by this time having disappeared, 
the chromosomes collect at the centre of the nucleus and pass on to the 
equatorial plate (Fig. 14). The spindle, which is composed of well-marked 
fibres, terminates bluntly at both ends (Fig. 1). This completes the history 
of the cycle of the nuclear division. 
Conclusion. 
It will be gathered that this investigation supports the views held by 
Strasburger ( 30 ) (1904) and by Gregoire ( 9 ) (1906) as regards the story of the 
somatic divisions. Gregoire has shown that in the alveolization of the 
chromosomes during the telophase, the chromosome band resolves itself 
into two parallel threads with an intervening clear space. The spaces become 
obliterated owing to the separation and interlacing of the fine threads, and 
thus a network is formed. A nuclear rest ensues. As the nucleus passes 
into the early prophase, the network is transformed into ‘ bandes alveolo- 
reticulees ou spongieuses ’, which are identical with the alveolar chromosome 
bands of the telophase of the preceding division. By progressive concen¬ 
tration the bands become homogeneous chromosomes. There are no 
chromatic discs. 
The somatic divisions of Galtonia follow the above summary of 
Gregoire in its general lines, and his plan can be adopted as the work¬ 
ing principle. Nevertheless, these nuclei exhibit great variations, variations 
