CYTOPLASMIC INCLUSIONS OF THE GERM-CELLS. 439 
the newly formed spermatid these bodies occupy the position 
shown in Pl. 23, figs. 12 and 13. At the time the mito- 
chondrial bodies begin to run together, the acroblasts, which 
are about three or four in number, gradually become vesi- 
cular. This process is quite easily followed out, and can 
often be seen occurring in the several acroblasts in one 
spermatid (see PI. 23, figs. 14 and 15, and the figures on 
PI. 25). In fact this process rarely seems to happen quite 
synchronously in one cell. When formed the acroblasts are 
quite spherical, and their wall is of equal thickness, not more 
bulging or thicker on one side than the other. Sometimes 
very small acroblasts are found (PI. 25, fig. 39). 
After the various other cell elements are arranged in final 
order, as shown in PI. 23, fig. 17, the acroblasts approach, and 
adhere to the nucleus very often at first as shown in PI. 23, 
fig. 17. In PI. 25, figs. 39, 40, 41, and 42, the formation of 
the acrosome is shown. PI. 25, fig. 41, is typical ; it shows two 
large acroblasts adherent to the nucleus ; where they touch the 
nucleus is a small, darkly-staining body, shown also in PI. 25, 
figs. 38, 39, 40, and 42. In PI. 25, tig. 42, the dark body is large, 
and the acrosome has been formed and is in its usual position. 
The dark dot is always touching the nucleus, and probably 
formed under its influence. One can sometimes find three or 
four acroblasts all adherent to the nucleus, each containing 
the dark granule. The question arises as to what occurs to 
the several acroblasts in such cases. I think the acrosome is 
finally formed by the running together of several acroblasts. 
This explains how such a large cap as that shown in PI. 24, 
fig. 20,- arises. At this stage it almost surrounds the nucleus. 
In PI. 25, figs. 47 and 51, other stages are shown; the four 
acroblasts are together forming one large acrosomic body, and 
in PI. 25, fig. 47, the running together of these structures has 
taken place. 
It will be seen from this account that the acrosome is 
formed from acroblasts, which can be found in the growth 
stage of the spermatocyte, and which act definitely, especially 
in division of the cells. In Text-fig. 3 this process is shown 
