THE NUCLEI OF UROLEPTUS MOBILIS 



319 



long axis of the spindle, and in no case is there any evidence of 

 V's or Y's. In some cases the rods appear to run unbroken 

 from pole to pole of the spindle (figs. 55, b). In other cases thera 

 may be more than four distinct chromosomes, sometimes five or 

 six or seven, in the nuclear plate. In still other cases there are 

 four definite chromosomes at the poles of the anaphase stage 

 (fig. 55, d). 



Until I can be convinced of the exact method of chromosome 

 division by further study of this phase, I will not offer an inter- 

 pretation of this puzzling problem. Let it suffice here to state 



54 



Figs. 54 and 55 Prophase, metaphase, anaphase, and telophase stages of 

 second maturation mitosis where four double chromosomes are reduced to four 

 single ones. Bouin fixation, iron-haematoxylin stain. X 3200. 



that the number of chromosomes is reduced from eight to four 

 by this second division. The four chromosomes of the anaphase 

 stage (fig. 55, d) lose their identity in the chromatin mass of the 

 late telophase (fig. 55, e). The final division of the nuclei is 

 rather abrupt, and there is no evidence of long connecting strands 

 between the daughter products. 



c. The third division. The products of the second division are 

 small granular micronuclei, usually four in number, which are 

 ready for the third division with no extensive intervening resting 

 stage. In some individuals all four of them undergo this third 

 division (fig. 57, left) ; in some only three, while in others only 



