Digby. — On the Archesporial and 
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PLATE VIII. 
Fig. i. 0 . palustris var. aurea. Polar view of anaphase of archesporial mitosis. Fission not 
visible in the chromosomes (S.F.). 
Fig. 2. Early telophase showing the splitting of the chromosomes into longitudinal halves or 
threads (S.F.). 
Fig. 3. The nucleus is bounded by a limiting membrane. Some of the individual split chro- 
mosome segments are still recognizable, while others have lost their visible identity owing to the 
separation of their beaded halves (threads) (S.F.). 
Fig. 4. 0 . palustris. The hreads become resolved into fine beads producing a cloudy effect 
(W.F.). 
Fig. 5. O. palustris var. aurea. The beaded threads tend to separate from one another, thus 
inaugurating a reticulum. In some of the chromosome segments the halves (threads) are still closely 
parallel (S.F.). 
Fig. 6. The beaded threads have completely separated, and the nucleus shows a faint reticulum, 
the chromatin being mostly concentrated in the nucleoli. This is the so-called 1 resting ’ stage (S.F.). 
Fig. 7. Very early prophase. The nucleus has a generally more active appearance, and a few 
large chromatic granules are present in the reticulum (S F.). 
Fig. 8. The granules of the reticulum become more distinctly chromatic (S.F.). 
Fig. 9. The chromatic granules incline to cluster and are of very varied sizes ; the meshes of 
the reticulum become wider (S F.). 
Fig. 10. Some of the threads of the reticulum break down, and the meshes open out, and thus, 
very gradually, the reticulum becomes converted into a spireme thread. At this stage there are 
indications of the fine spireme threads tending to arrange themselves in parallel pairs. This is the 
first sign of the reassociation of the threads, i. e. the longitudinal halves of the chromosomes which 
Separated during the preceding telophase (Fig. 4, &c.). Therefore each thread is of a half univalent 
nature. As prophase advances the reassociation becomes closer until the mature univalent chromo- 
some is organized (S.F.). 
Fig. 11. The beaded linin threads form striking parallelisms, as shown in the pair lying 
horizontally in the E. of the nucleus. Cf. this reassociation of the chromosome halves with the 
separation of the chromosome halves, as shown in Figs. 4 and 5. Note that the two approaching 
threads are precisely similar even to the correspondence of the beads (S.F.). 
Fig. 12. The linin threads become increasingly distinct and the chromatic beads show more 
definitely a parallel arrangement, and are often disposed in groups of four (S.F.). 
Fig. 13. A slightly later stage ; the chromatic beads are somewhat larger (S.F.). 
Fig. 14. The chromatin from the beads gradually infiltrates the linin threads, causing them to 
stain chromatically (S.F.). 
Fig. 15. A superficial section of a nucleus from the same sporangium as Fig. 14, showing some 
of the lengths of associating spiremes as fine parallel threads, whilst others are chromatic (S.F.). 
Fig. 16. 0 . palustris. This nucleus shows the close association in pairs of the threads, and the 
segregation of these paired individual segments suggestive of the future univalent chromosomes. 
Note the exact similarity of the approaching sides (H.). 
Fig. 17* 0 . palustris var. aurea. Note the marked association of the threads (S.F.). 
Fig. 18. Superficial section of a portion of a nucleus from the same sporangium as Fig. 17, 
showing that on the close association of two threads the resulting filament becomes considerably 
thickened (S.F.). 
Fig. 19. 0 . palustris. A later stage in which there is an almost complete approximation of the 
two parallel threads, and the space between them may now be distinguished as the line of fission. 
The spireme filaments curve and undulate, and many of the fine connecting transverse strands have 
disappeared (A. A.). 
Fig. 20. 0 . palustris var. aurea. The spireme filaments lengthen out, but are still undulating. 
In this particular nucleus fission is evident (S.F.). 
Fig. 21. Spindle fibres appear and converge towards the nucleus from four points (S.F.). 
Fig. 22. 0 . palustris var. undulata. The nuclear limiting membrane disappears, the chromo- 
somes concentrate, and vestiges only of fission are to be seen (S.M.). 
Fig. 23. 0 . palustris var. aurea. Oblique view of a metaphase. The chromosomes are thick 
and concentrated and show no fission (S.F.). 
