Pollen Mother-cells of Certain Plants. 61 
Fig. 21. Single bivalent chromosomes from equatorial plate, showing forms and method of 
separation of parts during metaphase: 21 a. Chromosomes being separated from within outward. 
21 />. Separation nearly complete. Four parts showing distinctly. 21 c, 21 d. Four parts of the 
chromosome showing as double V’s. 21 e. Double V’s nearly separated. 
Fig. 22. Side view of spindle showing chromosomes during anaphase. Each chromosome is 
two-parted as it passes to the poles. 
Fig. 23. Single anaphase chromosomes. Each chromosome two-parted : 23 a. Spindle 
attached at one end. 23 b. Spindle attached at one end, completely contracted. 23 c. Spindle 
attached at middle. 23 d. Chromosomes near the poles. 
Fig. 24. Showing arrangement of two-parted chromosomes at the spindle pole. 
Fig. 25. Polar view of daughter nucleus. Chromosomes very slightly changed in form. 
Fig. 26. Daughter nuclei. Chromosomes somewhat elongated, but still distinct. 
Fig. 27. Daughter nucleus showing chromosomes arranged into a pseudospirem. Each chromo- 
some may, however, be distinguished. 
Fig. 28. Single segment of pseudospirem from daughter nucleus. Each chromosome may be 
seen to be a two-parted structure. 
Fig. 29. Daughter nucleus in prophase of division. Chromosomes lie free in nuclear cavity. 
Fig. 30. Two daughter cells in division within mother-cell wall. One spindle seen from side 
and one from pole. 
Fig. 31. Anaphase of second division. 
Fig. 32. Single chromosomes forming univalent spirem in granddaughter nucleus. 
Fig* 33 * Young pollen grain, showing single chromosomes in the resting nucleus as distinct 
bodies (prochromosomes) arranged into a single series. 
