STUDIES ON GERM CELLS 409 



poses although iron hemotoxyUn was also employed. .The 

 hemalum does not stain the yolk if properly used. It is frequently 

 difficult to stain the early cleavage nuclei, but several hundred 

 preparations have furnished all the necessary stages required. 

 Division figures are comparatively rare and one can only conclude 

 that mitosis takes place very rapidly and is followed by a long 

 period of rest. 



The stage of development is not the same in all eggs at the 

 time of deposition, but usually the maturation divisions are in 

 progress or the first cleavage has begun. As shown in figure 44, 

 the polar bodies are produced about half way between the an- 

 terior and posterior ends of the egg. The nucleus of the egg 

 lies in an accumulation of cytoplasm at the periphery. Two 

 polar bodies are formed; then the female nucleus with its sur- 

 rounding cytoplasm moves out toward the center of the egg and 

 copulates with the male nucleus (figs. 7, A, and 45). The first 

 cleavage occurs at this point. The cleavage nuclei, each with a 

 small portion of cytoplasm, then move apart and divide almost 

 synchronously. Figures 44 to 51 were made from longitudinal 

 sections of eggs of various stages and all of the nuclei are here 

 represented in a single plane, but their relative positions are 

 indicated as determined by superimposing sketches made with 

 a camera lucida. It will be seen that the nuclei are more numer- 

 ous near the anterior end of the egg and that they become rather 

 evenly scattered throughout the yolk. There are of course no 

 cell walls and the thin strands of cytoplasm between the yolk 

 globules connect the cleavage nuclei. Each nucleus lies in a 

 sort of ameboid island of cytoplasm, forming a body equivalent 

 to a cell, but probably better designated by the term energid 

 (Sachs, '92). 



In figure 46 two energids are shown just after the first cleavage 

 division. Figure 47 represents the division of the first four 

 energids to form eight; those lettered a and c are in the anaphase 

 of mitosis, whereas b and d have reached the telophase. The 

 relative positions of the first four energids is indicated in figure 

 48 which was reconstructed from a series of transverse sections. 

 Here a condition exists quite similar to that shown in figure 47; 



