86 W. W. SWINGLE. 



PLATE IV. 



FIG. 20. Late anaphase of a dividing first spermatocyte showing the accessory 

 chromosome at one pole. 



FIGS. 21, 22 and 23. First maturation divisions showing single nature of acces- 

 sory chromosome. 



FIG. 24. First maturation division showing accessory chromosome at one 

 pole and single round chromosome at opposite pole. 



