I3O ALICE M. BORING. 



All figures were drawn with a camera lucida, 1/12 oil immersion and a 12 com- 

 pensating ocular, no reduction. All drawings but Fig. 4 are from acetocarmine 

 preparations. 



EXPLANATION OF PLATE I. 



FIG. I. Metaphase of spermatogonium, showing 17 chromosomes. 



FIGS. 2, 3. Spermatocyte growth stages, showing plasmosome (P) and two 

 stages of condensation in the odd chromosome (X). 



FIG. 4. Same stage as 3, but from permanent preparation fixed in Gilson. 



FIG. 5. Odd chromosome in different stages of growth. 



FIGS. 6, 7. Prophases of primary spermatocytes, 8 bivalents and i single odd 

 chromosome (X). 



FIGS. 8, 9. Metaphase spindles of primary spermatocytes, odd chromosome 

 (X) toward one pole. 



FIG. 10. Equatorial plate of primary spermatocyte, 9 chromosomes, odd chro- 

 mosome (X) to one side of the group. 



