642 Fraser . — Chromatin in Meiotic Divisions of Vicia Fab a. 
EXPLANATION OF PLATES XLIII AND XLIV. 
Illustrating Dr. H. I. C. Gwynne- Vaughan’s paper on the Meiotic Divisions in Vicia Faba, 
Magnification x 2,000 throughout. 
PLATE XLIII. 
Fig. 1. Pollen mother-cell with resting nucleus showing diamond-shaped mesh of reticulum. 
Fig. 2. Three stages in the separation of the reticulum and nuclear membrane. 
Fig. 3. Full synapsis; surface view. 
Fig. 4. Rather later stage, showing extrusion of nucleolus and beginning of formation of spireme. 
Fig. 5. Loosening of synapsis; two similar loops thrown out. 
Fig. 6. Same ; threads united end to end. 
Fig. 7. Same ; parallel association of threads. 
Fig 8. Same, rather later ; three distinct pairs. 
Fig. 9. Same. 
Fig. 10. Nuclear area filled by postsynaptic spireme showing fission; cross connexions have in 
this case persisted longer than usual. 
Fig. 11. Postsynaptic spireme; some paired strands recognizable, also fission of chromatin 
thread. 
Fig. 12. Second contraction. 
Fig. 13. Later stage of same, showing a conspicuous double loop, one end of which has been 
set free. 
Fig. 14. Second contraction ; several pairs of associated chromosomes may be recognized. 
Fig. 15. Same; longitudinal fission indicated in places. 
PLATE XLIV. 
Fig. 16. Five newly separated gemini. 
Fig. 17. Gemini, rather later stage. 
Fig. 18. The seven gemini on the equatorial plate. 
Fig. 19. Metaphase of first meiotic division. 
Fig. 20. U-shaped gemini of metaphase. 
Fig. 21. First meiotic division, showing longitudinal fission in the sister chromosomes. 
Fig. 22. Same; separation of the V-shaped sister chromosomes. 
Fig. 23. First meiotic division ; anaphase. 
Fig. 24. Same; telophase. 
Fig. 25. Cross attachment of chromosomes after first meiotic division. 
Fig. 26. Same ; showing both lateral and terminal attachments. • 
Fig. 27. Elongation of V-shaped chromosomes. 
Fig. 28. V-shaped chromosomes on second meiotic spindle. 
Fig 29. Second meiotic division ; anaphase. 
Fig. 30. Same ; telophase. 
Fig. 31. Very late telophase, showing fission and attachment of chromosomes. 
Fig. 32. Resting nuclei of young pollen grains, showing diamond-shaped mesh of reticulum. 
Fig- 33- Extrusion of chromatic bodies from nucleus of pollen mother-cell. 
