336 CALIFORNIA ACADEMY OF SCIENCES. [Proc. 3D Ser. 



The linin of the nucleus has gradually become more 

 prominent, staining a darker blue; but while in the pre- 

 ceding stage it showed as fine granular threads, it now 

 (fig. 6) appears as smooth fibers, running through the 

 nucleus, and usually more or less parallel to each other and 

 to the axis of the largest cone. The fibers stain blue. 



The cones, which are composed of granular threads, 

 increase in number. Some are larger; some smaller. 

 Usually one has the ascendency over the others, and this, 

 as a rule, is the first cone formed; it appears ordinarily at 

 one end of the ellipsoidal nucleus. As has been said, it is 

 usually parallel to the axis of this largest cone, and con- 

 sequently more or less parallel to the longer axis of the 

 nucleus, that the linin threads are directed. This seems to 

 indicate a polarity of the cell. 



In figure 6 we find the cones composed of granular 

 threads; these threads are in connection with the fibers of 

 the felt-like zone. In the next stage we find cones, large 

 and small, composed of smooth fibers. These fibers appar- 

 ently originate from the felt-like zone. But do they push 

 out of their own accord ? or are they pulled out by the 

 granular fibers ? or are the cones a result of a combination 

 of the granular fibers and those of the felt-like zone? 

 Judging from my preparations the last seems to be the 

 most probable. 



As soon as the fibers of the cone have become smooth, 

 the nuclear wall just below the cone breaks down, and the 

 fibers penetrate into the nuclear cavity, where they anasto- 

 mose with the linin threads. The two kinds of fibers can 

 hardly be distinguished, for while it is true that the fibers 

 originating from the cytoplasm are thicker than those 

 formed from the linin, even this difference very soon dis- 

 appears. 



Even at this early stage the fibers arrange themselves 

 in bundles (fig. 7), an arrangement which is far less promi- 

 nent in the fully developed multipolar stage, but which 

 reappears in the bipolar spindle. 



The chromosomes retain their original position for a long 



