294 Allen . — The Early Stages of Spindle- Formation 
continuity in spite of a very considerable displacement and 
distortion. In favourably stained sections, as that represented 
in Fig. 8 , the cell-wall is orange, and the plasma-membrane 
blue like the fibres and the nuclear membrane. In optical 
section, the two membranes and the larger fibres closely 
resemble each other in colour, density, and thickness. The 
dark rounded bodies seen in the cytoplasm in Fig. 8 are 
stained red, like the nucleole. They are doubtless the bodies 
which have been so frequently described as extra-nuclear 
nucleoles, and are to be found in many preparations from this 
stage onwards. They are often, though seemingly not always, 
in contact with the fibres; there is also a tendency for them to 
appear more numerously near the periphery of the cell than 
toward the interior, especially if the peripheral region is much 
vacuolated. Their number is much greater than that of the 
blue bodies noticed in earlier stages, so they can hardly be 
derived from those. Besides, the blue bodies are still 
occasionally to be seen. On the other hand, the nucleole 
shows no perceptible diminution in size or density. Its 
apparent irregularity of shape in the figures is largely due to 
cohering chromatin masses and linin fibres. There are often 
to be seen in the liquid surrounding the pollen-mother-cells, 
and usually clustered about the latter, red-staining bodies of 
very varying size, exactly resembling those noted in the 
cytoplasm. This suggests the possibility that both classes 
of red bodies are drops of unassimilated food substances, 
perhaps of soluble proteids, which have been precipitated by 
the fixing-solution. The absence of the membrane on one 
side of the nucleus in Fig. 10 is due to the fact that the 
section is cut close to the surface of the nucleus, and is partly 
tangential to it. 
When the extra-nuclear felt is fully formed (Fig. 12, PI. XV), 
there is a tendency toward a zonal arrangement of the cyto- 
plasm ; outside the felt is a granular region, and between this 
and the plasma-membrane a zone containing many fibres and 
little granular material. But fibres can sometimes be seen 
running out from the inner felt toward the periphery, as 
