466 



HISTOLOGY 



are bi-lobed, and split longitudinally into two equal halves. The split 

 appears first at one end, and the divided ends are opened into a V-- 

 shaped figure, and then 

 pulled apart until the V 

 is straightened out into 

 a line. At this point 

 they appear as a rod 

 with three lumps on it, 

 one on each end and a 

 larger one in the middle. 

 The break now comes 

 in the middle of the 

 central knob, and the 

 bi-lobed daughter chro- 

 mosomes move apart 

 toward their respective 

 poles (Fig. 434, C). 



In Figure 434, D, 

 may be seen a late telo- 



FIG. 433. Asterias Forbesn. A slightly younger ovum than , . ,. . . . 



the preceding to show the streaming out of chromatin to a pnase OI tniS division, 

 distant group of chromosomes. X 1500. (Drawn by H. E. anc j here it will be no- 



ticed that the distal end 



of the figure has emerged from the surface of the ovum., carrying a 

 little cytoplasm with it. This is the first polar body. 



FIG. 434. Aslerias Forbesii. Four stages in the first reduction division. X 1500. 

 (Drawn by H. E. Jordan.) 



Almost before the first polar body is completely separated, the chro- 

 mosomes in the ovum begin to form a new equatorial plate on a new 

 spindle derived from the remaining portion of the first spindle. Figure 



