PLATE 3 
EXPLANATION OF FIGURES 
Growth period—Continued 
19 Later leptotene showing the process of unwinding and expansion completed. 
20 and 21. Two cells in synizesis. 
22 and 25 Pachytene nuclei. 
23 and 24 Degenerating cells. 
25 to 28. Early prophase nuclei. The sex-chromosomes usually appear in 
this stage as a more or less spherical body. 
29 and 30 Later prophases showing elongation of the cell and position of the 
early centrosome. The nucleus has taken a peripheral position. The sex- 
chromosomes have become more conspicuous and very irregular in form. 
Primary spermatocyte 
31 Prophase chromosomes being drawn into metaphase position. 
32 Side view of a first spermatocyte metaphase. 
33 Polar view of the same. 
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