230 MARY T. HARMAN. 



PLATE III. 



FIG. 22. Union of univalent chromatin elements to form bivalent chromo- 

 somes. X is the odd-chromosome in all figures of this plate. 



FIG. 23. Bivalent chromosomes with the nuclear membrane present. 



FIG. 24. Bivalent chromosomes before the formation on the spindle. The two 

 elements of the third chromosome have not yet united. 



FIG. 25. First spermatocyte spindle showing the seven chromosomes. 



FIG. 26. Metaphase, lateral view of first spermatocyte division. 



FIG. 27. Early anaphase of first spermatocyte division. The odd-chromosome 

 approaching one pole in advance of the other chromosomes. 



FIG. 28. Metaphase plate, lateral view of second spermatocyte division. Four 

 of the chromosomes show the longitudinal split. 



FIG. 29. Metaphase plate, polar view of second spermatocyte division. 



FIG. 30. Metaphase plate, polar view of first spermatocyte division. 



