MARK AND COPELAND. — SPERMATOGENESIS OF THE HONEY BEE. 107 



During the migration of the interzonal body into the finger-like cell 

 process, other portions of the cell undergo conspicuous changes. The 

 extranu clear fibres which, in the earlier stages, extended from the 

 distal centrosome around the nucleus and the interzonal body to 

 the proximal centrosome, have now increased in number, and crowd 

 upon the nucleus. The latter continues to change in form and size ; 

 it becomes considerably flattened and much smaller. The chromosomes 

 are crowded together so that they often appear (Figure 10) as a single 

 deeply staining mass, generally much nearer the proximal than the 

 distal end of the cell, and sometimes actually in the projection of the 

 cell close to the interzonal body. Careful decolorizing at this stage 

 reveals the chromosomes in the form of dyads, with possibly an actual 

 separation of the dyads into their components. This perhaps repre- 

 sents what Meves describes as the breaking up of the chromosomes 

 into granules. 



Soon after this the cylindrical process of cytoplasm connecting the 

 interzonal body with the main portion of the cell becomes elongated 

 and more attenuated. Eventually it assumes a slender neck-like fonn, 

 and then by rupturing, effects a complete detachment of the interzonal 

 body from the spermatocyte (Figure 11). The region of greatest at- 

 tenuation and final rupture is such that a small, though possibly 

 variable, amount of undifferentiated cytoplasm is cut off with the 

 interzonal body. The r61e of this body in spermatogenesis is now 

 finished ; apparently it gradually diminishes in size (Figure 15), and 

 ultimately disappears entirely. 



The extranuclear fibres, which were well developed as far back as 

 the stage represented in Figure 4, are possibly concerned in some way 

 with the elimination of the interzonal body ; they are at no time con- 

 nected with any chromatin, and yet they are as large and stain as 

 deeply as the fibres within the nucleus. They persist and are to be 

 recognized in the cell throughout the succeeding division. 



At about the time of the detachment of the interzonal body the 

 nuclear membrane disappears and the spindle presents a form resem- 

 bling that which usually characterizes such a structure. The chromo- 

 somes are now seen to be in the metaphase (Figure 11), having 

 returned to the condition which they exhibited immediately before 

 the elimination of the interzonal body. 



The history of the nucleus during the elimination of the interzonal 

 body is hard to trace and difiicult to interpret. Meves states that, 

 after the formation of a spindle figure inside the persisting nuclear 

 membrane, with sixteen chromosomes irregularly arranged at the 

 equator, there is no further progress ; that, on the contrary, the chro- 



