Lewis. — Nervous Syst. Polychseta. 



PLATE 5. 



Figs. 27-30. Four successive sections through one cell. 



Fig. 27. Section tlirough nucleus, showing two nucleoli. 



Fig. 28. Section through nucleus and outer zone of sphere. 



Fig. 29. Section through sphere and centrosome. Both Figures 28 and 29 show 



the band of denser protoplasm partially surrounding the sphere. 

 Fig. 30. Section through sphere and centrosome, showing a central corpuscle, 



probably not the one shown in Figure 29. 

 Fig. 31. Section of giant cell, showing the outpocketing of the cell in which the 



nucleus is contained. 

 Fig. 31*. Section of cell from the region of the sub-oesophageal ganglion, showing 



nucleus and two spheres. 

 Fig. 32. Section immediately following the one shown in Figure 31. Radiations 



extend far out through the protoplasm of the cell. 

 Figs. 33, 33% 34. Sections through different giant cells, to show relation of the 



sphere and nucleus to the cell process. 



