7H 
Beer . — Studies in Spore Development . II. 
The diakinetic chromosomes can often be seen to be joined together 
by a number of delicate filaments (Fig. 23). 
Metaphase, Anaphase, and Telophase. 
Following on diakinesis we find the development of the spindle taking 
place in the usual manner. In Fig. 24 I have shown the six bivalent 
chromosomes of Tragopogon irregularly placed upon the multipolar, poly- 
arch spindle. A layer of denser cytoplasm lies just outside the spindle 
rudiment. The multipolar spindle later becomes bipolar in the way 
so often described in other plants. The chromosomes have meanwhile 
contracted very considerably, and some of their forms in this stage are 
shown in Fig. 25 for Tragopogon. In Matricaria the contraction of the 
bivalent chromosomes, which are nine in number, is even more notice- 
able, and they present considerable uniformity of shape in this plant. 
During the metaphase the univalent members of the bivalent chromo- 
somes become drawn apart, and are distributed to the two poles of the 
spindle during the anaphase. 
In Fig. 26 I have represented the end of the metaphase (or begin- 
ning of the anaphase) in Matricaria. The almost diagrammatic regularity 
in the form of the chromosomes is very noticeable in this drawing, and 
has not been at all exaggerated. 
In Fig. 27 is seen a later stage in the anaphase of Matricaria , whilst 
in Fig. 28 the chromosomes have reached their destination at the two 
poles, and are very closely aggregated together. The early and late 
anaphase in Tragopogon are illustrated in Figs. 29 and 30, respectively. 
In Tragopogon , as well as in Crepis , the chromosomes are at first 
very closely arranged together at the poles (Figs. 31 and 28). There is 
no nuclear wall about the groups of daughter chromosomes at this time, 
but a little later such a limiting membrane can be seen to have developed 
(Figs. 32 and 33 a). 
Just before the new nuclear wall is formed the chromosomes begin to 
separate slightly from one another. The appearance suggests that an 
unstained fluid is collecting between and around the chromosomes, and that 
this presses these bodies apart. Almost coincident with the separation of 
the chromosomes is the appearance of the new nuclear wall enclosing both 
the chromosomes and the fluid which has collected round these. 
In the later history of the nucleus there can be no doubt that an inter- 
change of materials takes place between the cytoplasm and the karyo lymph, 
and that at least some of the constituents of this fluid are derived from the 
cytoplasm. The manner in which the first nuclear sap collects between the 
massed chromosomes suggests, however, that this fluid is secreted within 
the chromosomes themselves, and probably within the vacuoles which can 
so often be seen in their substance at this stage. The fluid passes out from 
