PLATE 2 



EXPLANATION OF FIGURES 



6 Testis of Desmognathus. Longitudinal section. Fixed in Hermann's fluid 

 August 21 ; iron hematoxylin stain. Two lobes are shown, the lower end of the 

 one on the right being connected with the lower end of the one on the left. In the 

 larger lobe, the region of degenerated lobules occupies in the figure the upper 

 end. These are succeeded below by spermatozoa, maturing spermatozoa, trans- 

 forming spermatids, spermatids, spermatogonia, the boundary between the regions 

 occupied by the last two being well shown in both lobes. 



7 Testis of Desmognathus. Longitudinal section. Fixed June 7 in Hermann's 

 fluid; iron hemato.xylin stain. View of the lobules in the boundarj^ region. In 

 the upper three lobules are growing spermatocytes i; the intermediate three 

 lobules show synizesis; below these comes the boundarj' and lobules of sperma- 

 togonia among which many cysts are undergoing degeneration. 



8 Testis Desmognathus. Photograph of the boundary region, showing a 

 degenerating lobule, filled with debris, fat vacuoles, karyolytic nuclei and the nor- 

 mal nuclei of the follicle cells. Above the degenerating lobule the spermatocytes 

 I indicate a slight condition of synizesis. The lobule below contains spermato- 

 gonia. 



9 Testis of Desmognathus. Photograph simihir to that shown in fig. 8, from 

 the surface of the testis (on the right side of figure). One degenerating lobule is 

 shown and portions of two others contain degenerating cysts. 



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