EXPLANATION OF FIGURES. 



All drawings were made at a magnification of about 2,000 diameters and then re- 

 duced one third. All figures were drawn from Agalena unless otherwise specified, 

 and were drawn with the aid of the camera lucida. 



PLATE IX. 



FIG. I. Spermatogonium in resting stage. 



FIG. 2. Pole view of equatorial plate of spermatogonic monaster. 



FIG. 3. Spermatogonic monaster. 



FIGS. 4-5. Anaphase of spermatogonic monaster. 



FIG. 6. Daughter cell of last spermatogonial division showing disintegration of 

 the chromosomes. 



FIGS. 7-8. Resting cells. 



FIG. 9. Formation of spireme, " synapsis." 



FIG. 10. Completion of spireme. 



FIGS. 11-13. Coarse spireme with longitudinal split. 



FIGS. 14-15. Shortening and thickening of loops of segmented spireme. 



FIG. 16. Prophase of primary spermatocyte with loops transformed into V-shaped 

 chromosomes. 



FIG. 17. Splitting of chromosomes. 



FIGS. 18-20. Primary spermatocytic monaster. 



FIGS. 21-22. Sections of equatorial plate. 



FIG. 23. Primary spermatocytic metaphase. 



FIG. 24. Primary spermatocytic anaphase. 



FIG. 25. Late anaphase or telophase. 



. 26 . Reconstruction of daughter nuclei. 



FIGS. 27-28. Secondary spermatocytic monaster. 



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