SPERMATOGENESIS IN AMPHIBIA AND INSECTS 1a 
evidence of a degeneration of the mitochondrial elements such 
as Holmgren described in Silpha. The central substance (Bowen, 
22 b) was not demonstrable in my preparations, so that I have 
been unable to check Holmgren’s account of this feature. 
Summary 
1. The acrosome arises in connection with the Golgi apparatus 
plus idiosome, in a manner similar to that described in several 
other animals. 
2. The nebenkern passes through a series of condensation 
phenomena similar to those of the Hemiptera, and is completely 
divided only with the disappearance of the chromophilic sub- 
stance. 
ORTHOPTERA 
The development of the acrosome in various groups of Orthop- 
tera has been studied by many workers with very discordant 
results, a short résumé of which I have given in another place 
(Bowen, ’22a). Most of these cases, however, have been easily 
interpreted on the basis of conditions found in the Hemiptera, 
but in the case of the grasshopper the facts are as yet by no 
means clear. It was with the hope of clearing up the whole 
problem of the acrosome in Orthoptera that this study was under- 
taken. Thus far I have had opportunity to examine only a few 
species from the families Acrididae and Tettigoniidae. 
Family Acrididae 
Although the grasshoppers have been studied by many workers 
there has been a uniform failure to make out any details what- 
ever concerning the acrosome. Indeed, Buchner seems to have 
been the only one who even noted its occurrence. According to 
his latest account (Buchner, ’15), the acrosome is derived from 
the ‘proximal’ centriole by a process of division—an origin which 
is obviously quite different from that to be expected on the basis 
of my hypothesis. As a matter of fact, Buchner failed to make 
out most of the essential stages, due to the fact that the cyto- 
