Figs. 69-70. First spermatocyte, metaphase.
71. First spermatocyte, equatorial plate.
72. First spermatocyte, metaphase, showing metakinesis of the heterochromosomes.
73-74. First spermatocyte, anaphase.
75-76. Second spermatocyte, equatorial plates.
77. Second spermatocyte, showing metakinesis of the small chromosome (s).
78. Second spermatocyte, prophase, showing chromosomes longitudinally split.
79-80. Young spermatids, n the chromatin nucleolus.
81-87. A series of stages in the development of the sperm head, showing the various phases in the history of the chromatin nucleolus (n).
88. Cross-sections of nearly mature sperm heads.