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



EXPLANATION OF PLATE XXXIV. 



Fig. 7. The nuclear wall has nearly all disappeared and the linin has now 

 formed a network. The perikaryoplasm is being gradu- 

 ally transformed into a network of threads which stain deep 

 violet, in contrast to the orange of the surrounding peri- 

 karyoplasm. 



Fig. 8. This stage is about the same as fig. 7, only the network appears 

 to be of a more definite nature. 



Fig. 9. The nuclear wall has entirely disappeared and the area once occu- 

 pied by the nucleus is now filled with a clear network of 

 threads ; where the threads cross one another granules are 

 present. The entire contents of the cell is now beautifully 

 differentiated into three parts: the outer cytoplasmic reticu- 

 lum which stains light blue ; perikaryoplasm which stains 

 orange, and the central network which stains deep violet. The 

 figure alfeo shows that the central network has in three places 

 grown out into projections. 



Fig. 10. This shows the projections to have grown considerably and the 

 meshes of the central network are more elongated, as if pulled 

 out. 



Fig. II. In this figure the projections have grown out to such an extent 

 and the meshes have become so elongated that they form dis- 

 tinct fibres. The more definite the fibres, the more deeply vio- 

 let they stain. The figure also shows the vacuolated nucleolus. 



Fig. 12. This stage is probably earlier than fig. 11, as there are no fibres 

 developed as yet. It shows the central network grown out in 

 three distinct projections, and we have the outline of a multi- 

 polar spindle. 



