87. Later stage of spermatid, showing condensed chromatin, elongated centrosome (c), acrosome material (a), and spindle-remains (s).

88-89. Older spermatids, showing formation of acrosome (a) and middle piece (m).

90-92. More advanced stages.

93. Mature spermatozoön.

Blattella germanica.

Fig. 94. Somatic cell from egg follicle, 23 chromosomes.

95. Spermatogonium, showing chromatin element (x) associated with a nucleolus (n).

96. Same, prophase of mitosis.

97. Equatorial plate of spermatogonial mitosis, 23 chromatin elements.

98. Young spermatocyte, showing centrosome (c) and U-shaped element (x).