SPERMATOGENESIS IN AMPHIBIA AND INSECTS 13 
distinguish with certainty, but it seems to increase in size, and 
when the Golgi bodies clear away from the nucleus it is a very 
conspicuous object. This globule is the acrosome. It now 
migrates around to the opposite side of the head (nucleus) (fig. 
25), always retaining its close contact with the nuclear wall. As 
it moves it becomes differentiated into a basal, plate-like portion 
which rests on the nucleus, and a small knob directed toward 
the cell wall (fig. 25), the whole reminding one of a collar-button. 
As the head begins to elongate in the manner characteristic of 
the insect sperm, the basal portion of the acrosome becomes 
drawn out into two rod-like lugs which extend back over the 
surface of the nucleus for a short distance and apparently serve as 
a means of anchorage for the acrosome (fig. 26). The distal 
portion becomes drawn out as a little ball on the end of a short 
rodlet. Very frequently this can be divided into two—a duplex 
condition which is possibly the characteristic one, though visible 
only when the sperm head is favorably turned. As the head 
draws out, the acrosome retains, for a time, this rod-and-ball 
structure; its ultimate history has not been studied. 
Unfortunately, the exact method by which the acrosome is 
produced has not been made out. The separate Golgi bodies 
are themselves so small that in my preparations I was not able 
to follow the history of each individual. It seems probable, how- 
ever, that from each one is differentiated its small proportionate 
share, and by the deposition of many such parts the acrosome is 
gradually built up. Instead of the Golgi bodies’ fusing to form 
a single acroblast from which the acrosome is differentiated in 
toto as in most animals, each Golgi body is an acroblast in itself 
and the acrosome arises as a fusion product of the portions con- 
tributed ‘by each such ‘acroblast.’ This all fits in with the facts 
which I have made out in the Hemiptera. In the pentatomids 
I was able to show that occasionally the Golgi elements fail to 
fuse on time, and in such cases each partial acroblast produces 
its own acrosome of a size proportionate to the available material 
(Bowen, ’22a, fig. 54). Thus, what may be an occasional 
accident in the bug becomes in the grasshopper the customary 
procedure. 
