Cell Structure, Growth and Division in the Antheridia of Polytrichum etc. 187 
Plate VII. 
Dividing androgones of various generations. 
Figs. 30 — 32. The nuclear membrane has disappeared, and the chromosomes 
are in a knot in the equatorial region ; the spindle fibers are increasing in number. In 
Figure 32 the chromosome knot seems to be loosening. 
Fig. 33. The chromosomes becoming disentangled; in polar view. 
Fig. 34. The rearrangement of the chromosomes. 
Figs. 35 — 40. The equatorial plate stage. 
Figs. 41 — 48. Polar views of the chromosomes in the equatorial plate. 
Fig. 49. A metaphase. 
Figs. 50 — 53. Anaphases. 
Figs. 54, 55. Diaster stages. 
Fig. 56. A polar view of a cell at the same stage as that shown in Figure 55. 
Figs. 57, 58. Telophases; the spindle fibers are apparently increasing in number 
preparatory to cell plate formation. In Figure 57, equatorial swellings appear on a 
few of the fibers. 
Plate VIII. 
Figs. 59 — 65. Dividing androgones in telophase ; various stages in cell plate 
formation. In Figure 65, cell division is complete; the daughter cells are separated 
by the new partition wall. 
Figs. 66 — 90. Androcyte mother cells. 
Figs. 66, 67. Each androcyte mother cell contains a single central body. 
Fig. 68. A polar view of the central body and its aster. The nucleus, lying 
at a lower focus, is shown only in outline. 
Figs. 69 — 71. The division of the central body. 
Figs. 72 — 76. The divergence of the daughter Centers. 
Fig. 77. The daughter Centers in their final positions; the spindle is outlined. 
Fig. 78. The swelling of the nucleus and the beginning of spirem formation. 
Fig. 79. A polar view of one of the daughter Centers at about the stage of Figure 77. 
Figs. 80 — 82. The further swelling of the nucleus until its membrane is in con- 
tact with the central bodies. In Figure 82, the equatorial aggregation of the spirem. 
Fig. 83. A polar view of a nucleus at about the stage of Figure 82. 
Figs. 84, 85. Lateral and polar views of androcyte mother cells after the Segmen- 
tation of the spirem. 
Figs. 86 — 88. The gradual contraction of the nucleus. 
Fig. 89. A polar view of a contracting nucleus. 
Fig. 90. The further contraction of the nucleus ; the membrane has become in- 
distinguishable at an unusually early stage. 
Plate IX. 
Stages in the division of the androcyte mother cells. 
Figs. 91, 92. Polar views of cells whose nuclei are contracting ; the spindle 
fibers are seen (in section) in an extranuclear zone. 
Figs. 93 — 96. Cells whose nuclear membranes have disappeared; the chromo- 
somes in a knot. 
