Il8 MARGARET REED LEWIS AND WM. REES B. ROBERTSON. 



PLATE II. 



FIG. u. J. G. First spermatocyte, late prophase. Nuclear wall still intact, 

 "two masses of mitochondria. 



FIG. 12. Unstained. First spermatocyte metaphase. Mitochondria threads 

 have migrated towards the poles of the spindle. Zeiss 8 oc. 2 mm. lens. 



FIGS. 13, 14, 15. Unstained. First spermatocyte division. Same cell at 

 9:30 A.M. (Fig. 13), 9:45 A.M. (Fig. 14), and 10:10 A.M. (Fig. 15). Mitochondria 

 are long threads close to the spindle fibers. Zeiss 4 oc. 2 mm. lens. 



FIG. 16. Unstained. Mitochondria are granular threads around the spindle. 

 Those in the middle of the spindle occur underneath. The sex chromosome at one 

 pole. Spindle outlined at one pole. Leitz Binoc. 40 X 1/12 lens. 



FIGS. 17, 1 8, 19. J. G. First spermatocyte division in the same cell. Fig. 17 

 at 9:40 A.M., Fig. 18 at 9:50 A.M., and Fig. 19 at 10:45 A.M. Zeiss 6 oc. 2 mm. 

 lens. 



FIG. 20. J. G. End of first spermatocyte division. Mitochondria migrated 

 .into two daughter cells. Chromosomes granular. Leitz Binoc. 40 X 1/12 lens. 



