334 CALIFORNIA ACADEMY OF SCIENCES. [Proc. ,^u Ser. 



they become very narrow, being usually from two to three 

 times as long as broad. The fibers are covered with gran- 

 ules; they begin to stain a deeper blue than the other fibers. 

 This appearance extends only partially around the nucleus, 

 usually about half way (fig. 2.) 



Changes now begin to take place in the cytoplasm farther 

 away from the nucleus: the cytoplasm loses its uniform 

 appearance; here and there fibers have begun to thicken, 

 or granules have accumulated upon them. These fibers 

 stain a deep violet and show sharply against the lighter 

 background (fig. 3). They are arranged in more or less 

 conical groups with their bases directed toward the nucleus. 



Very gradually, almost imperceptibly, the granules 

 around the nuclear wall increase in number, and a second 

 layer of elongated meshes is laid down next the one already 

 formed. In the meantime the granules situated upon and 

 between the fibers have disappeared, and the fibers have 

 become thick and smooth (fig. 3). We now see the nucleus 

 partly surrounded by a number of rectangular meshes 

 elongated in a direction parallel to the nuclear wall. 



These processes seem to continue for some time, until 

 finally three or four layers of elongated meshes have been 

 laid down around the nucleus. Then the radial fibers of 

 these meshes begin to disappear, leaving a zone composed 

 of fibers running parallel to the nuclear wall. That this 

 zone is not attached closely to the latter can be easily 

 observed in later stages when one or more spaces exist 

 between the nuclear wall and the fibrous felt-like zone, 

 which stands out clearly as a dark blue band. 



In the meantime granules have continued to accumulate 

 around the nucleus, and the meshes of the cytoplasm adjoin- 

 ing the felt-like zone have grown smaller. Together they 

 form a distinct zone (the granular zone) which possesses a 

 distinct outer boundary. 



The cell now presents the appearance indicated in figure 

 4. The chromatin appears in the form of lumps, which 

 like the nucleolus, stain a brilliant red. Here and there 

 linin, in the form of violet-staining granular threads, may 



