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



EXPLANATION OF PLATE XXX. 



All figures were drawn with the Abb^ camera lucida. Objective, Zeiss 

 Horn. Imm. ^^\ Comp. ocular, No. 6. 



Fig. I. A young pollen-mother-cell. The cytoplasm consists of elon- 

 gated meshes. 



Fig. 2. Change in cytoplasm. The meshes of the layer immediately 

 adjacent to the nucleus become smaller. Beginning of accu- 

 mulation of granular matter around the nucleus. 



Fig. 3. Formation of violet-staining fibers in conical groups in the cyto- 

 plasm. The fibers parallel to the nuclear wall have become 

 smooth. 



Fig. 4. A dense granular zone has accumulated around the nucleus. 



Fig. 5. Granular fibers have appeared in the granular zone. 



Fig. 6. Formation of cones. More or less parallel linin threads are seen 

 in the nucleus. 



