614 



ROBERT ]r. BOWEX 



directly into th<^ acrosorue. After tlie acrosome is formed 

 the Golgi complex as a wliolc^ is cast off and has no further 

 connexion of any kind with the acrosome. I have recently 

 developed my views on this subject in a more general form 

 (Jjowen, 1922 e), and it will be the purpose of this section to 

 show how the observations of Gatenby can be harmonized with 

 my previous results. 



The early steps in the formation of the acrosome cannot be 

 analysed with any satisfaction in Callosamia on account 

 of the very small size of the acrosome in this form. In 

 Pygaera my material begins at a point where the acrosome 

 is already nearing completion. I will accordingly refer to 

 Gatenby's figures for tlic earliest stages, the essential features 

 of which are also shoAvn clearly in the older spermatids of my 

 Pygaera preparations. 



My observations contirm the statement of (jatenby and 

 Woodger (1921) concerning the casting off of the (iolgi bodies, 

 but I would go further and state that not merely ' nmch ', but 

 all of the Golgi apparatus is thus disposed of. The Golgi 

 bodies can be seen in any of the older spermatids at var^ang 

 distances from the nucleus (figs. 8, 10, 13, 46, and 4H), and in 

 much later stages they can be found scattered in groups at 

 various points along the sperm tail. Furthermore, they show 

 no evidence of a vesicular structure, but they do show, in favour- 

 able cases, the differentiation into Golgi rodlet and idiosomic 

 substance which I have found to be so characteristic of them 

 in the primary spermatocyte. How then does the acrosome 

 arise ? Gatenby's figs. 36 and 37 indicate, I believe, the 

 essential features of the answer to this question. In these 

 figures each of the acrosomic vesicles has attached to one side 

 a Golgi rodlet, the idiosomic substance not being shown. 

 I have been similarly unable to make out the idiosomic material 

 in Pygaera, but the conditions in Callosamia leave 

 no doubt that it is present, but temporarily obscured, after 

 ordinary staining, by the development of the vesicles. In 

 other words I would interpret the vesicles as differentia- 

 tion — rather than direct transformation — products of 



