234 MICHAEL F. GUYER. 



FIG. 16. Late anaphase of division in a secondary spermatocyte which has 

 received the two accessory chromosomes. Each of the latter divides as an inde- 

 pendent chromosome at this time. 



FIG. 17. One end of a late anaphase of a division in a secondary spermatocyte 

 which had not received the accessory chromosomes. 



FIG. 1 8. Two contiguous spermatids, one without chromatin nucleoli, the 

 other with two. The spermatids in general are about equally divided into these 

 two classes. 



FIG. 19. Nucleus of a primary spermatocyte showing two chromatin nucleoli. 



