Fig. 12. The fibers have broken up and the whole has assumed a vesicular appearance, resembling a blackberry. The acrosome is present.
Fig. 13. This shows a persisting spermatid stage. The chromatin appears in patches. The nebenkern is in the ball-and-ring stage. The acrosome shows its characteristic clear center surrounded by a ring darker on one side. The two dark bodies on the nuclear surface are probably artefacts.
Fig. 14. A stage a little later than 13. The dark central ball shows some vacuoles. The cell is beginning to elongate.
Fig. 15. Same as fig. 14, with the ball denser.
Fig. 16. The nucleus has become almost clear. The acrosome is behind the nebenkern.
Fig. 17. This shows the axial filament apparently growing out from the nucleus. There is an aggregation of chromatin at its base.
Fig. 18. The axial filament passes over the nebenkern, which has slightly elongated. The accessory chromosome is very plain.
Fig. 19. a shows a surface view, and b an optical section, of a nebenkern which is in process of breaking up.
Figs. 20 and 21 have part of the surface fibers cut off and show the dark mass forming within.
Fig. 22. Shows a nebenkern passing from the blackberry stage into the ring stage.