STUDIES ON INSECT SPERM ATOGENESIS. 351 



Other cases can readily be found in which the casting off of a 

 remnant by the acrosome has not been mentioned but is never- 

 theless indicated (see for example Terni, '14). If then the anlage 

 of the acrosome presents this bipartite character, how is the 

 acrosome itself derived and what is the nature of the cast off 

 remnant? I believe that the facts which I have described in the 

 Hemiptera offer a decisive answer to this question, and at the 

 same time point the way to a new conception of the acrosome 

 which may clear up the confusion in which we find ourselves at 

 present. 



In Euscliistus we find in the primary spermatocytes a number 

 of scattered Golgi bodies characterized by a duplex structure. 

 On the one hand there is a heavily stained peripheral zone, the 

 " Golgi apparatus " of authors, and on the other a central non- 

 staining or chromophobe substance to the nature of which I will 

 return later. In the maturation divisions these bodies undergo 

 fragmentation into dictyosomes which, having been distributed 

 in equal amounts to the spermatids, undergo progressive fusion 

 until a single mass (acroblast) is formed, the "sphere" of many 

 authors. This mass presents the same staining affinities as did 

 the Golgi bodies of the spermatocytes, a darkly staining periph- 

 eral layer and a chromophobe interior. Although it has not been 

 possible to offer conclusive proof of the exact homology of these 

 two substances in spermatocyte and spermatid, I think it can 

 scarcely be doubted that we have in this mass (acroblast) the 

 direct reconstitution of the structure of the spermatocyte Golgi 

 bodies. In other words, the material (acroblast) from which the 

 acrosome is to be derived is the Golgi apparatus.' 1 By a process 

 of differentiation connected with the chromophobe material oc- 

 cupying the interior of the acroblast (Golgi apparatus}, and 

 probably at its expense, there is formed a large, vesicular body 

 containing a small granule, which together form the acrosome of 

 the sperm. The remnant of the Golgi apparatus is cast off and 



1 I have used the term Golgi apparatus as covering the Golgi bodies (and 

 acroblast) as a structural whole, a usage which seems to be justified for the 

 present in the light of the possibilities which are discussed in the following 

 section on the structure of the Golgi complex. As I have there pointed out, 

 the restriction of the term Golgi apparatus to the part impregnated by the 

 customary methods is very possibly an artificial limitation. 



