THE RELATION BETWEEN AMITOSIS AND MITOSIS. 



97 



mitosis more frequently in slower growth. But until other data 

 are described theoretical considerations are out of place. 



III. THE EARLY STAGES OF THE FEMALE REPRODUCTIVE 



ORGANS. 



The ovary itself does not appear in the earliest stages of devel- 

 opment of the female organs. It is in fact formed only after a 

 considerable portion of the ducts has differentiated. The earliest 

 visible stage in the development of the female organs is the 

 increase in the number of nuclei in a region immediately adjoin- 

 ing the longitudinal nephridial canals. Viewed from the surface 

 it appears as in Fig. i, A. A somewhat later stage is shown in 

 Fig. i, B. The nuclei are more closely packed together here 



than elsewhere consequently the region stains more deeply. This 

 region differentiates later on into the middle region of the repro- 

 ductive ducts. Sections through this region at this stage show a 

 'number of nuclei often surrounded by more or less cytoplasm 

 without definite boundary. These nuclei are indistinguishable 

 from the other parenchymal nuclei except that many of them are 

 smaller. Parenchymal fibers can often be traced from the cells 

 and the region is not marked off in any way from the parenchyma. 

 But the most interesting point forpresent purposes is the appar- 

 ent absence of mitosis in these regions. Although the writer has 

 examined hundreds of sections of these early stages he has never 

 seen a single case of mitosis. Yet it is very evident that an ex- 

 ceedingly rapid multiplication of nuclei is taking place, for the 

 size of the area and the number of nuclei increases rapidly with 



