538 
karyokinetic figure of this stage when compared with that seen in 
Fig. 2 is most striking. From centrosome to centrosome the spindle 
of Fig. 2 measured 49 « while in the stage shown in Fig. 3 the 
distance from the center of one centrosome to that of the other was 
99 u. And not only has there been an increase in the length of the 
spindle, but both the astrocoels and the centrosomes have also increased 
greatly. The chromosomes have now a simple rod-like form, and the 
astrocoels are clear areas of considerable extent, in which only a few 
achromatic fibres can be seen, but at their periphery a somewhat 
granular zone, not represented in the figure and not very clearly 
distinguishable from the cytoplasm, could be made out. The astral 
rays have increased both in number apparently and in length, extending 
throughout the entire cytoplasm, those from each astrocoel seeming to 
cross to a certain extent opposite the equator of the spindle. The 
centrosomes, however, have undergone the most remarkable changes, 
and are now vesicular structures with perfectly homogeneous contents. 
From the periphery of each a number of achromatic fibres radiate out 
into the astrocoel, a deeply staining granule occurring at the point of 
insertion of each fibre into the wall of the centrosome. In Fig. 3 
Fig. 3. Fig. 4. 
Fig. 3. Karyokinetic spindle in which the chromosomes have almost reached the 
poles, The entire protoplasmic area is shown, the clear circles around it being yolk 
granules. The scale of this figure is half that of Fig. 2. 
Fig. 4. Centrosome from spindle represented in Fig. 3 showing the achromatic 
network on its surface. 
the centrosomes are represented as seen in optical section, but if the 
focus be altered its spherical form becomes apparent, and one gets 
the appearance represented in Fig. 4, which shows not only the deeply 
