Plate XXV 
Primary Spermatocytes 
Fig. 17. Early leptotene nucleus, showing xx and y 
Fig. 18. Trifle later stage than Fig. 17, xx and y in close apposition. 
Figs. 19-20. Nuclei of syndetic cells, xx and y connected. 
Figs. 21-22. Diplotene nuclei, showing separation of xx and y-elements. 
Figs. 23-24. Early strepsistene nuclei, showing reunion of xx and y. 
Figs. 25-26. Later strepsistene nuclei, showing fusion of xx and y. 
Fig. 27. Late strepsistene, showing the formation of the nucleolar spherule 
(nl) 
Figs. 28-29. Primary spermatocytes, metaphase plates, polar view, showing 
12 chromosomes. 
Figs. 30-33. Primary speratocytes metaphase, lateral view, showing xxy-hexad 
Fig. 34. The twelve chromosomes of a primary spermatocyte metaphase, 
xxy on extreme right, taken from a section. 
Fig. 35. Same stage as figure 34, except that it was taken from a smear slide. 
Fig. 36. Various forms of the xxy-hexad, as seen in metaphases and anaphases 
of primary spermatocytes viewed laterally, y-element shown above in each case. 
