32O LELIA T. PORTER. 



EXPLANATION OF PLATE I. 



All drawings were made with the aid of a camera lucida at table level. A Zeiss 

 microscope with compensating 12 ocular and 2 mm. oil immersion objective was 

 used. The drawings have been reduced one third off. 



i. 2. Equatorial plate of spermatogonia. 



3, 4. Tetrad stages, showing all chromosomes. 



5. Polar view of first spermatocyte. 



6-8. Side view of same. 



9. Early anaphase of first division. 



10. Side view of first spermatocyte division. 



11-13. Polar view of second spermatocyte. 



14-20. Second spermatocytic division. 



21, 22. Spermatids, corresponding daughter cells. 



23, 24. Spermatids, corresponding daughter cells. 



