526 



P. W. WHITING 



Successively later stages, as judged by relative position of the 

 cysts, are shown in figures 3, 4, and 5. The nucleolar elements 

 are darker in these stages. They tend to appear separate at 

 first (fig. 3), and to fuse later. The nucleolus then gradually 

 becomes diffuse while the chromosomes thicken and stain more 

 densely. Figure 6 represents an optical section of a nucleus at 



Spermatogonia 



' Prophases 



is is 



17 18 19 



20 2i 22 23 1 Metaphases 



24 25 28 ~f . 



Anaphases 



Telophase 



First Spermatocytes 



Growth Stages 



J Prophases 



J Meta-, Anaphases 



Telophases 



Interkinesis 

 i B } Prophases 

 - — Meta-, Ana-, Teloohases 



Spermatids 



►Spermatozoa 



Text Figure 1. Location of stages in the gonad 



this stage. The separate chromosomes can not yet be made out, 

 but a thick chromatic cord is attached to the diffuse nucleolus. 

 Two terminal granules, each connected to the tip of the chro- 

 matic thread to which the nucleolus is attached, are of interest 

 as they appear again in first spermatocyte prophases. They 

 are here diffusely stained and suggest by their form the an- 

 tennae of a butterfly. 



