PLATE 6 



EXPLANATION OF FIGURES 



79 Same stage as figure 78. Centrosome rod shown clearly. 



80 Spermatid with chromatin of nucleus more condensed. Thread-like 

 structure in middle of nebenkern vacuole. Mitochondria between nebenkern 

 and nucleus as well as distal to nebenkern. 



81 Same as the preceding, but threads of nebenkern have broken and now 

 form vesicles. 



82 Same as the preceding showing linear arrangement of small vesicles. 



83 Spermatid of a slightly later state than the preceding. 



84 Spermatid with nebenkern contents thrown off. 



85 and 86 Spermatids. Side and surface view adjacent cells to show relation 

 of axial filament to middle-piece anlage. Filament thicker on account of mito- 

 chondrial granules in relation to it. 



87 Spermatid showing mitochondrial granular mass in relation to middle- 

 piece and axial filament. 



88 Spermatid showing secondary relationship to middle-piece anlage. 



89 Spermatid. A later stage to show mitochondrial ribbon about the proxi- 

 mal part of the axial filament. 



90 Spermatid nucleus elongating and staining darker. Middle-piece getting 

 longer. 



91 Same as the preceding. 



92 Elongation of nucleus of spermatid. Mitochondria about filament. 



93 Spermatid. A still later stage, no mitochondria shown. 



94 Spermatid nucleus very much drawn out. Acrosome at apex and darker 

 part indicates position of middle-piece. 



95 Part of anterior end of mature spermatozoon. The undulating membrane 

 with its thicker border is well shown. 



422 



