enter sTnapsls Irregularly, in a sort of one -at-a- time fashion 

 but they tarry here tmtll all of the cells In the greater part 

 of the tuhule have reached this stage, then the nuclei of a 

 given portion all proceed to the open spireme stage, shown in 

 Pigs. 11 and IE. These figures show only the chromatin which 

 lies on the side from which the nucleus was observed. The 

 chromatic material is again arranged in the peripheral portion 

 of the nucleus and is segregated Into the chromosomes which 

 become somewhat massed In the center of the nucleus. The 

 spindle next makes its appearance (Fig. 13 J and the chromosomes 

 are drawn into the equatorial plate (Pig. 14). 



The mitotic figure represented in Pig. 15 shows the pos- 

 sibility of a tri-polar division. Such a condition may have 

 been brought about by the formation of one of the spindles of 

 the second division before that of the first division was com- 

 pleted. There is a small portion of the chromatin of this 

 nucleus that is not Involved in the mitotic figure. This 

 portion is shown at £., in Pig. 15a which Is a drawing of 

 what was seen at a lower level than that shown in JTig. 16. 



The chromosomes in these nuclei are so small and so close- 

 ly crowded together it is very difficult to determine their 

 structure or their number. In one preparation, however, I 

 obtained a ring-shaped appearance of the chromosomes lPig.l6). 

 These forms were seen in the equatorial plate and also before 

 the chromosomes had been arranged in the plate. In most of 

 the preparations the chromosomes appear as mere granules. It 

 may be that the ring shaped forms were produced by the fixing 



