Il6 MARGARET REED LEWIS AND WM. REES B. ROBERTSON. 



EXPLANATION OF PLATES. 



J. G. = Janus green stain. 



N. R. = neutral red stain. 



Mitochondria = black-inked granules and threads. 



Neutral red granules = gray granules outlined with black ink. 



Centrosome = clear round granule about same size as neutral red granule. 



PLATE I. 



FIG. i. N. R. Blind end of follicle. Apical cell surrounded by primary 

 spermatogonia. The somatic cells form the boundary 'of the follicle. Round 

 neutral red granules in the apical cell and also in the somatic cells. Leitz Binoc. 

 4b X i /i 2 lens. 



FIG. 2. Unstained cell. Primary spermatogonium. Mitochondria are granu- 

 lar threads. Clear region at upper side of the cell is probably the mitosome (spindle 

 remains). Leitz Binoc. 4b X 1/12 lens. 



FIG. 3. J. G. and N. R. Apical cell. Mitochondria are small black granules 

 and the neutral red are the larger gray granules. Zeiss 6 oc. 2 mm. lens. 



FIG. 4. J. G. Two secondary spermatogonia still attached together. Chro- 

 mosomes granular. Telophase. Mitochondria are not in nucleus but around it. 

 Leitz Binoc. 4b X 1/12 lens. 



FIG. 5. Same cell as Fig. 4. Globules of blue which form after the mitochon- 

 dria have lost their stain. 



FIG. 6. J. G. Secondary spermatogonium. 



FIG. 7. J. G. First spermatocyte, centrosome divided. Sex chromosome. 

 Early prophase. 



FIG. 8. J. G. First spermatocyte. Diplotene nucleus stage. Centrosomes. 

 Two masses of mitochondria, one on upper surface of cell and one on the lower. 

 Leitz Binoc. 4b X 1/12 lens. 



FIG. 9. Unstained. First spermatocyte 'bouquet-stage' synapsis. Zeiss 6 oc. 

 2 mm. lens. 



FIG. 10. J. G. Spermatogonium, telophase. Each chromosome is in a 

 separate vesicle and is granular. Nuclear wall reforming from chromosome 

 vesicles. Leitz Binoc. 4b X 1/12 lens. 



