154 RAYMOND BINFORD 
plate may be shown to have a structure like that represented 
in figure 16a. This was drawn from a section cut from the 
edge of the plate. Here it appears that the chromosomes are 
stretched as they are pulled apart. Strands of chromatin pulled 
out between the separating groups of chromosomes may be seen 
in the later stages of the anaphase. By more extensive destain- 
ing we may obtain what appear to be only the cores of the 
chromosomes as shown in figure 16 b. 
In figures 17 to 22 various stages in the anaphase are repre- 
sented. The interzonal fibers and the mid-body are very dis- 
tinct in figures 19 to 21. 
The second miotic division follows very soon after the first. 
The chromosomes become somewhat separated and are then 
drawn together again into the equatorial plate ready for the 
second division (figs. 23 to 25). Figure 26 shows the beginning 
and figure 27 the end of the anaphase. Here again the inter- 
zonal fibers and the mid-body are distinctly seen and a portion 
of the cytoplasm is definitely associated with each daughter 
nucleus. The nucleus of the spermatid is now organized and 
persists in a sort of resting condition for a comparatively long 
time. The centrosome may also be distinguished for a consider- 
able time, but later I was unable to recognize it (figs. 28 to 32). 
A clear space surrounding the nucleus is also seen in these figures. 
The spermatid as it appears in figure 32 rests for a considerable 
period before any change towards the formation of the sperma- 
tozoon is observed. The boundaries between the cytoplasm of 
the different cells disappear and the nuclei come to lie in a sort 
of plasmodium. 
The transformation of the spermatid into the spermatozoon 
In serial sections of a single tubule we may trace every stage 
in the transformation of the spermatid into the spermatozoon, 
and since the two ends of the series are in opposite ends of the 
tubule and the intermediate stages lie in serial order between 
these ends, we may use the position of a seminal element in the 
tubule as a criterion for determining its relative stage in the 
