630 L. K. Cary, 



The resting- nucleus in the oocyte is similar to that in one of 

 the seg-raentation cells. In the maturation stages, however, even 

 before the formation of the equatorial plate, the nucleus becomes 

 elongated in a direction corresponding to the long- axis of the eg^. 

 In every observed instance where the maturation division was 

 taking- place, one end of the nucleus was close to the wall of the 

 cell, and. indeed, usually in contact with it. In the eggs still 

 attached to the ovary the nucleus is apposed to the cell wall at 

 the broad, distal, end of the egg. In those egg-s in the young- 

 sporocyst which were undergoing their maturation while free in the 

 body cavity, there was, of course, nothing by which any definite 

 orientation could be determined. In all cases, however the shape 

 of the egg was elliptical instead of nearly spherical as in the 

 segmentation cells. 



The formation of the spireme for the maturation division differs 

 very markedly in one respect from the same process in one of the 

 segmentation nuclei. In the maturation division I have never found 

 a stage corresponding to that in the segmentation division, where 

 the greater part of the contents of the nucleus are gathered up 

 into a single central mass wiiicli is "suspended" from the nuclear 

 membrane. 



In the maturation division, on the other hand, the caryosome, 

 although it increases slightly in size, never becomes a lightly 

 staining mass. While granules can be recognized in the caryosome 

 after it has reached its greatest size for this division, they are from 

 the first, larger and less distinct than in the segmentation nucleus. 

 They immediately fuse to form the spireme thread, which lies in 

 the densely staining mass of nucleoplasm, that formerly surrounded 

 the caryosome. 



On the growth of the spireme this densely staining area increases 

 in size, and becomes lighter in color until it is finally indistinguish- 

 able from the remainder of the nucleoplasm. 



The fully developed spireme in the maturation division occupies 

 a smaller portion of the nucleus than does the spireme in the 

 segmentation divisions. It is always confined to the portion of the 

 nucleus nearest the cell wall of the egg (Fig. 32). The chromosomes 

 are formed from the spireme in the manner already described for 

 the segmentation divisions (Fig. 33). 



In Fig. 36 and 37, which are drawings from eggs undergoing 

 their maturation free in the body cavity of the sporocyst the 



