132 ALICE M. BORING. 



EXPLANATION OF PLATE II. 



FIGS, ii, 12. Anaphases of primary spermatocyte division, odd chromosome 

 (X) undivided at one pole. 



FIGS. 13, 14. Two pairs of secondary spermatocytes, X present in only one 

 of each pair. 



FIG. 15. Abnormal secondary spermatocyte, 16 chromosomes and i odd chro- 

 mosome (X). 



FIG. 16. Metaphase of secondary spermatocyte, all chromosomes dividing. 



FIGS. 17, 18. Equatorial plates of secondary spermatocytes, one with 8, the 

 other with 9 chromosomes. 



FIG. 19. Anaphase of secondary spermatocyte, no lagging chromosome. 



