202 W. E. AGAR 



Fig. 23. — Resting primary spermatocyte. 



Figs. 24, 25. — Fragments of developing leptotene nuclei to show con- 

 version of the massive blocks of the resting spermatocyte into the leptotene 

 threads. 



Fig. 26. — Leptotene nucleus. 



Fig. 27. — Synizesis and sjrndesis. 



Fig. 28. — Three short lengths of conjugating chromosomes from three 

 different zygotene nuclei. 



Plate 14. 



Fig. 29. — Syndesis complete. 



Fig. 30. — Early pachytene nucleus, synizesis loosening out. 



Fig. 31. — Pachytene stage, with two compact bodies, presumably X 

 and Y. 



Fig. 32. — Later stage. X and Y, one of them greatly pulled out, uniting 

 into a bivalent. 



Fig. 33. — Late pachytene nucleus showing evidence of commencement of 

 diplotene stage. Chromatoid body in the cytoplasm. 



Fig. 34. — Early diplotene nucleus. Chromatoid body in cytoplasm. 



Fig. 35. — Three bivalents from an early diplotene nucleus. 



Fig. 36. — Late diplotene nucleus, chromatoicls in cjiioplasra. 



Fig. 37. — A pair of young secondary spermatocytes, still connected by 

 the spindle remains. Note larger and bilobed chromatic body in the upper 

 nucleus. Chromatoids in the cytoplasm of one cell. 



Fig. 38. — Outline drawings of four nuclei, about the stage of fig. 32, 

 to show relations between the sex chromosomes and the plasmosome. 



