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



EXPLANATION OF PLATE XXXVIII. 



Fig. 7. Differs but slightly from fig. 6. The transformation of the nuclear 

 wall has progressed farther and the wall is interrupted at several 

 points. 



Fig. 8. Is similar to figures 6 and 7. The alteration in the nuclear wall, 

 however, is still more marked; the linin is more abundant, its 

 threads are coarser, contain more granules, and stain more 

 deeply. 



Fig. 9. The cell resembles that represented in fig. 8. The nuclear wall has 

 apparently been transformed into a meshwork which forms one 

 continuous network with the cytoplasmic reticulum on one side 

 and with the linin reticulum on the other. The quantity of linin 

 has increased. 



Fig. 10. Is much like fig. 9, although the transformation of the nuclear wall 

 has not progressed so far. The appearance of this and the two 

 following figures might give rise to the suspicion that the sec- 

 tions of the nucleus are not median and that the appearance of 

 the network filling the nuclear cavity is due to focussing on the 

 inner surface of the nuclear wall. Careful focussing, however, 

 shows conclusively that this is not the case. 



Fig. II. The nuclear wall, as such, is no longer to be distinguished. In 

 some places it forms a fibrous belt two or three meshes in width. 

 These fibers stain more deeply than any others; they are coarser 

 and contain more granules; they help to form the continuous 

 network which fills the cell. In one place every trace of the 

 nuclear wall is lost; nothing remains to mark the transition from 

 linin reticulum to cytoplasmic reticulum. The granular part of 

 the cytoplasm now forms a complete zone between the fibrous 

 belt representing the nuclear wall and the cell-wall. 



Fig. 12. Every trace of the nuclear wall has disappeared. There is nothing 

 to even indicate its position, and an uninterrupted network 

 stretches from cell-wall to cell-wall. The granular zone referred 

 to in fig. 1 1 is well marked. 



