HO C. M. CHILD. 



the karyosome retain the stain and the presence of the spireme 

 would not be suspected. The writer is firmly convinced by long 

 experience with this stain that it is of little or no value in de- 

 termining differences of chemical constitution ; size, density, and 

 permeability seem to be the chief factors determining which parts 

 shall retain the stain. 



The spireme appears first in the central portions of the ovary 

 adjoining the end of the oviduct and proceeds in all directions dis- 

 tally along the follicles. The follicle tips continue, however, to 

 divide amitotically for some time after the other portions of 

 the ovary have entered the spireme-stage. Fig. 21 shows the 

 tip of a follicle at this stage. In the same ovary the cells near 

 the oviduct were like those in Fig. 20. Fig 22 is a nearly longi- 

 tudinal section through the terminal portion of a follicle showing 

 the different stages at different levels. In all but one of the five 

 cases with spiremes most of the chromatin is outside the plane of 

 section. In this ovary all the cells have entered the spireme- 

 stage except those in the terminal region of the follicles and 

 division has already ceased there. 



Together with the nuclear changes occur marked changes in 

 the cytoplasm. The amount of cytoplasm increases in marked 

 degree as the figures show. It also stains more deeply than 

 before. During synapsis the nucleus is usually more or less 

 asymmetrical in position. In many cases at least the greater 

 amount of cytoplasm is on that side of the nucleus against which 

 the spireme is massed. (Figs. 20, A, 20, C, 20, D, 20, E, 23, A, 

 23, B}. It cannot be stated positively that this is always the case 

 but it is certainly of frequent occurrence. After fixation in chrom- 

 oxalic a regional differentiation of the cytoplasm is visible in many 

 cases and is perhaps a characteristic feature. As noted above, 

 the spireme usually becomes massed at one side of the nucleus : 

 this is followed by the appearance in that part of the cytoplasm 

 nearest the spireme of an area staining more deeply than any 

 other part of the cytoplasm (Fig. 24, A]. If extraction is carried 

 too far this area is scarcely or not at all visible. It is compar- 

 able to certain of the differentiations which have been called yolk 

 nuclei in other eggs and its appearance is followed almost im- 

 mediately by the formation of yolk granules which in Moniczia 



