432 E. L. SHAFFER. 



EXPLANATION OF PLATE III. 



Photomicrographs taken at a magnification of about 1,500 diameter?. 



FIG. 23. Resting secondary spermatogonia, showing diffuse granular mito- 

 chondria deeply staining in iron-hcematoxylin. 



FIG. 24. Telophase of a secondary spermatogonium, showing the deeply stain- 

 ing cell-plate. The rest of the spindle here shows somewhat darker than it really 

 is; it always takes the plasma stain. 



FIG. 25. Late prophases of first spermatocyte; Flemming fixation. The 

 mitochondria are filar, with their lengths extended in the direction of the chief 

 axis of the cell; the nuclei here are uncut and somewhat out of focus. Fig. 250 

 is a section at right angles to the chief axis of the cell and shows the mitochondria 

 on end view. 



FIG. 26. First spermatocyte from a Hermann fixation. The mitochondria 

 are agglomerated in dense masses (m). 



FIG. 27. Part of a cyst of first spermatocytes to show the spindle remains (5) 

 forming a connection between several cells; parts of it stain deeply with iron- 

 haematoxylin. 



FIG. 28. First spermatocyte greatly destained to show the cytoplasmic vacu- 

 ole of unknown significance. 



