128 GERM-CELL CYCLE IN ANIMALS 



between the daughter nuclei (Fig. 40, D). In 

 either case, however, the spindle remains persist, 

 forming a basic staining strand with enlarged ends 

 connecting the two nuclei. Since at this time and 

 in all later stages the two or more spermatogonia may 

 be found surrounded by an envelope of epithelial 

 cells, it seems certain that, as Wieman (19106) 

 maintains, the spermatozoa in a single cyst are 

 derived from a single spermatogonium. 



A cyst containing four spermatogonia is repre- 

 sented in Fig. 40, E. Here again appear the strongly 

 basic staining spindle remains connecting the nuclei. 

 These black strands persist until the succeeding 

 mitotic division occurs as Fig. 40, F, which was 

 drawn from a section of a cyst containing eight 

 spermatogonia, shows. Spindle remains are still 

 evident in later stages, as in Fig. 40, G, which repre- 

 sents a cyst containing thirty-two spermatogonia, but 

 were not observed in cysts containing more than 

 sixty-four cells. 



Many investigators have figured spermatogonial 

 divisions which result in rosette-like groups of cells 

 similar to that represented in Fig. 40, F. Ap- 

 parently, however, the spindle remains, if present, did 

 not possess such a strong affinity for basic stains. 

 Furthermore, only those of my preparations that 

 were fixed in Carnoy's fluid and stained in iron 

 hsemotoxylin exhibited these black strands. Similar 

 spindle remains have been observed in Dytiscus, 

 especially by Gunthert (1910), and Carabus (Go- 

 vaerts, 1913), during the differentiation of nurse 



