THE REDUCTION OF THE CHROMOSOMES 



235 



FIG. 87. Nuclei from microsporocytes of Vicia faba, showing parasynapsis. 

 Synigesis beginning in No. 6. X 1900. 



FIG. 88. Heterotypic prophases in spermatocyte of Tomopteris onisciformis. 

 A, pairing of leptotene threads beginning. B, pairing complete in some threads and 

 only beginning in others. C, conjugation complete; pachynema stage. D, resplittmg 

 of pachytene threads (separation of conjugated chromosomes.) (After A. and K. E. 

 Schreiner, 1905.) 



