46 SEXUAL REPRODUCTION IN CERTAIN MILDEWS. 



substance (figs. 56, 57). Frequently they may be much elongated by 

 further separation of the young daughter nuclei, but this is not neces- 

 sary to their disappearance. 



The chromosomes are next found loosely aggregated at the poles 

 and still plainly connected to the central body by the fibers which drew 

 them back from the equatorial plate region (fig. 56). This results in 

 a sort of diaster stage (fig. 57), though the significance of the name 

 does not appear in any conspicuous arrangement of the chromosomes. 



A nuclear membrane is next formed, close in to the surface of the 

 chromosomes at first, but soon expanding so that more or less clear 

 space appears around the mass. The chromosomes themselves seem 

 to be the cause of this enlargement. They grow in length backward 

 from the center, at the same time swelling and becoming somewhat 

 irregular and knotted (fig. 58). As a result we get at once a rough 

 duplicate (fig. 59) of the spirem stage of the prophases. From the 

 central body coarse, irregular threads are seen extending back into the 

 enlarging nuclear cavity. 



I have studied these stages carefully, and it seems very clear that 

 we have here, in reverse, the same process by which the chromosomes 

 were segregated out of the spirem-strands of the prophases. The sub- 

 stance of the chromosome is being redistributed in the rapidly growing 

 achromatic linin substance. The general resemblance between the con- 

 ditions in figs. 58-59 and 47-48 is certainly noteworthy and shows clearly 

 that the chromosomes in passing over into the so-called resting-stage 

 in the reconstitution of the daughter nuclei do not lose their connection 

 with the central body. 



As the reconstitution of the daughter nuclei progresses, the nucle- 

 oles reappear and the distribution of the chromatin becomes progress- 

 ively more irregular. The strands become longer and apparently may 

 become more or less connected by anastomosing fibrillae. The connec- 

 tion with the central body is, however, still perfectly definite and con- 

 spicuous (figs. 60, 61). The irregularity of the strands may be inter- 

 preted as due to a diminished tension in their connection with the central 

 body as compared with the prophase stages. Ultimately the chromatin 

 may become quite evenly distributed through the nuclear cavity, and 

 from the polar view appears much like an ordinary reticulum. But the 

 constant conspicuous attachment of the strands with the central body 

 is maintained even though, as is quite commonly the case, the nucleus 

 projects on that side in a short cone or papilla (figs. 59-61). 



As in the nuclei of the ascogenous hyphae, the attachment of this 

 apparent reticulum to the center becomes especially conspicuous if the 



