5O J. T. PATTERSON AND LELIA T. PORTER. 



PLATE II. 



FIG. ii. Metaphase plate of the second spermatocyte. 



FIG. 12. Side view of the second maturation spindle, showing four twisted 

 chromosomes. 



FIG. 13. A section through one side of the spindle, showing two chromosomes 

 that have just divided. Parts of two other chromosomes are also present. 



FIG. 14. A similar section, showing the complete division of four chromosomes- 



FIG. 15. Anaphase stage, showing eight daughter chromosomes passing to 

 each pole. 



FIG. 16. Late anaphase stage. 



FIG. 17. Telophase stage. 



FIG. 1 8. The two spermatids, still connected by means of the interzonal fibres. 



FIG. 19. A completely separated spermatid. 



FIG. 20. A later stage of the spermatid. 



