316 TAKU KOMAI 
part of the nuclear cavity (fig. 18). I could not determine: 
whether or no there is such a regularity in the orientation of 
particular chromosomes as is maintained by Nichols (’06) in the 
cases of Oniscus and Porcellio. In the stage succeeding, the 
chromosomes travel toward the equatorial region of the nucleus, 
whose membrane in the meantime vanishes and the achromatic 
spindle-fibers make their appearance (fig. 21). In the polar 
view of the metaphase (figs. 19 and 20) a few chromosomes 
overlie some others. It needs hardly be mentioned that the 
chromosomes are very large as compared with those appearing 
in the spermatogonial mitoses. The reduced number of chro- 
mosomes is twenty-four. The daughter-nuclei produced pass. 
directly into the succeeding division without entering into the 
resting stage. In the equatorial plate of the latter division 
twenty-four chromosomes again seem to be found, but I could 
not accurately determine the number; the chromosomes are: 
considerably smaller than those occurring in the preceding 
division. 
The chromatoid body is visible throughout the above succes- 
sive stages, virtually without undergoing any perceptible change 
altogether. It lies usually close to the nuclear membrane, and 
when the spindle is formed, it is always situated outside of the 
latter. Varieties of form found in spermatogonial cells are also: 
discernible. 
TRANSFORMATION OF SPERMATID INTO SPERMATOZOON 
At the end of the second maturation division, the chromo- 
somes group themselves at the poles of the spindle so closely 
together that they form a compact chromatin mass (fig. 22). 
Soon, however, clear spaces make their appearance within the 
mass (fig. 23), which rapidly increase in size, until the entire 
nucleus comes to exhibit a reticular structure. This change of 
the nucleus is shown in figures 23 to 26. Around the reticular 
nucleus is often seen a clear space devoid of granulation (fig. 26,. 
the cell on the left side). The chromatoid body is still present. 
The nucleus maintains the reticular state for a fairly long 
time; then some of the meshes of the network coalesce and 
