474 
J. BRONTE GAT ICN BY. 
length of the sperm together, is shown by the fact that one 
cannot find many straggling acroblasts (see PI. 26, fig. 10), 
and that the latter are able to form an acrosome upon the 
surface of the larger nuclei in later stages of degeneration. 
Even in normal stages the steps which lead to the formation 
of the acrosome from the acroblasts are never exactly syn- 
chronous in a sperm nest, but they rarely vary beyond certain 
limits. In the spermatocyte and spermatid the acroblasts are 
semilunar in shape in normal stages, and this shape gives 
way to a vesicular one. Now the acroblasts in abnormal 
spermatids quite often show a tendency to shrink and become 
darkly staining at a stage when in normal cells the acrosomic 
granule is being secreted, and since these darker acroblasts 
are often found removed from the nuclei, it might be possible 
to assume that the changes leading to the formation of the 
acrosome are not wholly dependent upon the nucleus. This 
seems to be supported by the fact that the acroblasts, when 
not in the immediate neighbourhood of the nucleus, may be 
found even in normal stages of different degrees of meta- 
morphosis towards acrosome. Another significant fact is 
supplied by PI. 26, fig. 9, which shows a part of an abnormal 
spermatozoon-nest in which the nuclei, though normally recon- 
stituted after the second maturation division, have failed to 
keep their position in the cell (see also PI. 26, figs. 3, 5, 7, 8, 
10, 11, and 12), but on drifting down have been followed by 
the acroblasts, which have formed complete acrosomes. The 
latter (A.) are normal in every degree, but the nucleus has 
failed to develop synchronously, and the curious condition is got 
of one element racing another in metamorphosis. The fact to 
be noted at present is that the acrosome can be formed without 
the synchronous steps in the nucleus. The sharp acrosome in 
PI. 26, fig. 9, belongs to a stage when the nucleus is also elongated 
and when it has regained its affinity for nuclear stains. If the 
metamorphosis of the acroblasts depended absolutely upon the 
nucleus one would get these bodies still vesicular and just about 
to apply themselves to the nucleus, but instead they are now 
fully formed. I would interpret PI. 26, fig. 9, as follows : 
