555 



stage; one nucleus (a) is preparing for mitosis in the manner charac- 

 teristic at this stage, but immediately adjoining it on the left is a case 

 of amitosis and numerous other cases occur in the same follicle. 



As the development goes on the cell-boundaries gradually appear 

 and mitosis becomes more 

 frequent, though I think 

 there is little doubt that 

 many of the nuclei never 

 divide mitotically until 

 maturation . 



I have not observed 

 in the ovary any degene- 

 ration of groups of nuclei 

 such as appears in the 

 testis. The ovarian nuclei 

 sometimes give oif very 

 small nuclei (Fig. 7 b, 



Fig. 8 c), some of which seem to degenerate and add to the cyto- 

 plasm, but apparently all the larger nuclei give rise to ova. 



The vitellarium or yolk-gland becomes distinguishable at a rela- 

 tively early stage from the ovary proper by the deeper staining of 

 its cytoplasm. Later, granules accumulate in the cytoplasm and the 

 characteristic yolk-cells are formed. Figure 11 shows parts of two 



Fig. 10. 



Fig. 11. 



follicles of the vitellarium with frequent amitoses. I have not thus 

 far found any cases of mitosis in the vitellarium and am inclined to 

 believe that mitosis does not occur there. 



