Meiotic Nticlear Divisions of Galtonia candicans. 739 
Synapsis. 
The nucleus lies excentrically in the cell (PL LXI, Fig. 43), the chromatin 
mass being always on the side of the narrow strip of cytoplasm (Fig. 43). 
The spherical nucleolus, more or less hidden by the chromatin, projects 
into the clear nuclear cavity (Figs. 42 and 43). In some cases two nucleoli 
are present. There is no definite nuclear wall, the nucleus is bounded by 
cytoplasmic fibrils, and this continues throughout the subsequent stages, 
a wall only reappearing at the anaphase. 
There is an important difference between this account of the presynaptic 
and synaptic stages of Galtonia and that given by Miyake (21). He describes 
the massing of the chromatin in the presynaptic stages into ‘ zygosomes ’. 
The zygosomes are double ; the halves each represent a somatic chromo¬ 
some. They collect in synapsis and retain their individuality. When the 
knot loosens the chromatin from each zygosome streams into a thread and 
thus forms the double thread of the spireme. Each thread represents 
a univalent chromosome. Zygosomes have not been seen in these prepara¬ 
tions. Throughout the presynaptic stages there is a doubling in the 
arrangement of the chromatin, but the chromatin is present in the form of 
variously sized and shaped portions ; there is no concentration into definite 
centres. With prolonged staining with Heidenhain, followed by much 
decolorization, darkly staining patches can be distinguished in the synaptic 
knot, as Gregoire (10) (1907) has described in his observations on Galtonia ; 
but, as he points out, these appearances are solely due to excessive 
differentiation in which all control of the stain has been lost. Sometimes 
in a favourably stained slide it is possible to distinguish a linin matrix in 
which irregular chromatin masses are embedded (Fig. 42); but as a rule the 
knot, at close synapsis, stains practically uniformly and resembles a heap of 
tightly compressed blocks in which no structure can be seen (Fig. 43). 
Thus synapsis in Galtonia faces one as an impenetrable wall. Great and 
far-reaching changes and rearrangements are possibly proceeding, but any 
suggestion as to their nature can be but merely speculative. 
The synaptic stage is one of long duration, judging from the frequency 
with which it is found. At synapsis the pollen mother nuclei of all the 
anthers of a bud may be found to be at this stage, whereas before synapsis, 
and especially after synapsis, there is an extensive range in the nuclear 
phases in the anthers of a single bud. For example, one anther may show 
its nuclei to be entering on the * open spireme ’ stage, whilst the nuclei of 
another anther may have fully formed chromosomes. Or, again, one anther 
may have its nuclei in ‘ diakinesis ’ preparatory for the heterotype division, 
whilst the nuclei of another may be completing the homotype division. 
There is also a considerable difference in the progressive nuclear stages, not 
