36 H- L. WIEMAN. 



nuclear area the chromosomes are in the form of single rods whose 

 free ends extend toward the polar body. There is every appear- 

 ance to indicate a resistance of the part of the chromosomes 

 against a tension pulling toward the polar body. Distinct spindle 

 fibers are not to be seen, but the cytoplasm contains a reticular 

 structure which may represent a poorly developed spindle. The 

 polar body is quickly cut ofif from the cell to which, however, it 

 may remain attached for a considerable length of time (Fig. 15). 

 The free polar body of Fig. 8 belongs to a cell in an adjacent sec- 

 tion. Polar bodies cut in various planes are frequently seen in 

 the spaces between spermatocytes at this time (Figs. 8 and 16) 

 and throughout the second spermatocyte division. The complete 

 absence of polar bodies in cysts containing cells with the chro- 

 mosomes in the looped condition of Figs. 5 and 6 makes it almost 

 certain that the looped stage precedes that of Figs. 7 and 8, in 

 which the chromosomes show free ends. 



Preparations for the second spermatocyte division follow very 

 rapidly. After the formation of the polar body, the second sper- 

 matocyte rounds up; the knot of chromosomes separates into 

 distinct, short, thick, curved rods, 12 in number (Fig. 9). 

 In the cell figured here, a late prophase, the nuclear mem- 

 brane is fairly distinct. Details of spindle formation were 

 not observed. Figs. 10 and 11 show characteristic side-views of 

 spindles at metaphase. The chromosomes seldom lie in one 

 plane so that counting even in polar views is a difficult matter. 

 In such views, as in Figs. 12 and 13, 12 chromosomes can be 

 counted with considerable accuracy in the majority of cases. 



A characteristic late telophase is shown in Fig. 14 which re- 

 sembles to a striking degree a somatic mitosis, and strongly 

 suggests that the chromosomes have been divided longitudinally. 

 In later stages of this division (Fig. 15) the chromosomes become 

 packed into dense compact masses, so that it is impossible to 

 determine the number of constituent chromosomes in the 

 daughter groups. When reconstitution of the nuclei occurs 

 (Fig. 16), these masses break up into slightly bent rods of ragged 

 outline. In cross section these rods appear as dots of which 12 

 can often be counted. Counts of the daughter groups of chro- 

 mosomes made in this way are not very satisfactory, since one is 



