GAMETOGENESIS OP SACCOCIRRUS 7 



is found a group of perfectly spherical granules at x. These 

 went black-brown in the OSO4 ; their true nature or origin 

 was not ascertained, but it was thought that ultimately they 

 formed a part of the spermatid, as will be shown later. The 

 number of granules was about twelve in all the cases I could 

 count. 



(c)The Spermatocyte Divisions. 

 PI. 1, fig. 4, is a first spermatocyte metaphase. The peculiar 

 yolk-spherules have taken up a position at the middle of the 

 spindle, and in the next stage (PL 1, fig. 5) the granules have 

 become sorted out into two groups (y) subequal in size. Each 

 spermatid (PI. 2, fig. 8) receives about one-quarter of the 

 number of granules in the spermatocyte. The behaviour of 

 the mitochondria in the divisions is peculiar : they lose their 

 granular state, and during the prophases break down to form 

 threads as in PI. 1, figs. 4 and 5, in the telophase (PI. 1, fig. 5) ; 

 the threads lie chiefly around the equatorial plate. The 

 Golgi rods are difficult to follow through mitosis ; at the 

 prophases they lose their staining power, and it is only in 

 certain cases that the cell at metaphase has distinguishable 

 elements (xy in PI. 1, fig. 4) which might be identified as Golgi 

 elements. It must be admitted that no positive evidence 

 has been adduced with regard to the Golgi elements during 

 division of the Saccocirrus spermatocyte. 



(d) The Newly-formed Spermatid. 

 In PI. 2, fig. 8, is a newly-formed spermatid. The yolk- 

 spherules (y) are on the right, while the mitochondria surround 

 the nucleus ; the Golgi elements are at ga, being scattered. 

 In the next stage the mitochondria collect to one side of the 

 cell, in proximity to the nucleus, the Golgi elements lying behind, 

 as in PI. 2, fig. 9 ; this cell was drawn from a Kopsch prepara- 

 tion, and in it no yolk-spherules could be identified. At x are 

 what I consider to be two of the granules marked similarly 

 in fig. 2. In nearly all Kopsch or Mann-Kopsch preparations 

 the spermatid cytoplasm is seen to be formed of very coarse 

 reticulum, as shown in PL 2, figs. 9 and 14. 



