10 j. bronte gatenby 



5. The Fate of the Tail of the Spermatozoon 

 DURING Entry. 



Buchner (3) showed that the sperm-tail sometimes entered 

 the egg, sometimes not. I have been able to confirm these 

 observations. In PI. 3, fig. 25, is a typical oocyte to illustrate 

 this : the sperm-head (sp) is wrapped around the oocyte 

 nucleus, while the remains of the tail of the sperm are, in this 

 section, seen as four irregular chromophile bodies at set. 

 In PL 3, fig. 22, in the lower oocyte, the sperm-head is at bp, 

 while the tail is cut across as two irregular bodies at spt. 

 In the ujjper cell of fig. 22 the sperm-tail seems to be partly 

 inside the egg (upper) and partly outside (lower). 



While it is generally impossible to say whether these irregular 

 masses (which we can positively identify as remains of the 

 sperm-tail) are, or are not, inside the egg cytoplasm, when 

 we examine eggs at a little later stage of growth, it is quite 

 certain that in the majority of cases the sperm-tail fragments 

 have not only entered the egg but have broken up to form 

 a number of spherical, extremely chromophile, bodies at the 

 periphery. In PI. 3, figs. 24, and 23 at spt, the beads are noted 

 all around the periphery of the oocyte. 



If Mann-Kopsch preparations be examined for this, the beads 

 appear a pale yellow colour as in PL 3, figs. 19 and 21, at spt. 

 In some cases it certainly appeared that the imniber of beads 

 derived from the remains of the tail of the sperm increased 

 in number as the egg grew. This was probably w^hat van 

 Gaver and P. Stephan thought when they believed that the 

 spermatozoa might have something to do with yolk-formation. 

 I do not believe, however, that the beads take part in fertiliza- 

 tion or yolk-formation, either directly or indirectly. 



Later on they either disappear or become hidden by the 

 formation of clouds of yolk or nucleolar deutoplasm (described 

 below). 



6. The Oogenesis of Saccocirrus^. 



The oogenesis has proved the most difficult problem that 

 I had hitherto attacked, and at one time I despaired of ever 



