460 ELMER L. SHAFFER. 



PLATE II. (Fics. 13 TO 22). 



FIG. 13. Secondary spermatogonium with characteristic chromatin nucleolusi 

 chromatoid body, and granular mitochondria localized at one end of the cell. 



FIG. 14. Spermatogonium in early stage of degeneration. Mitochondria are 

 larger due to agglutination, and nucleus is polymorphic. 



FIGS. 15, 16. Later stages in degeneration of spermatogonia. Mitochondria 

 continue to agglutinate and form large lipoid globules. 



FIG. 17. Pachytene bouquet stage of spermatocyte, showing persisting sex- 

 chromosome (A'), the macrochromosome loop (AA) and the filar mitochondria 

 localized about the idiozome (id.). 



FIG. 18. Stages in the condensation of the ring tetrad of the macrochromosome 

 pair (A A). 



FIG. 19. Similar stages in the formation of the small ring tetrad of the BB 

 chromosome pair. 



FIG. 20. Early prophase of the first maturation division. 



FIGS. 21, 22. Formation of first maturation spindle; mitochondria enveloping 

 the spindle. 



