Figure legend

Figure 4 Proximal-to-distal serial cross sections through the nucleus (Fig. 4a) and the neck (Figs. 4b to 4g) in a mature sperm, showing the relationships among nucleus (N), centriole derivative (C), principal mitochondrial derivative (M') and second mitochondrial derivative (M''). A, B, C = A-, B-, C-fibre of the centriole derivative triplets. d = dense lines connecting a triplet with two others. g = granular material present within the nucleus indentation and surrounding the neck components. Nm = nuclear membrane; Sm = sperm plasma membrane; SF = secondary fibres. Glutaraldehyde-osmium fixation, Vestopal embedding. X 120,000.

Figure notes

The sections do not appear to be strictly serial.