Lewis. — Nervous Syst. Poljchseta. 



PLATE 1. 



Figs. 1-3. Sections from three giant ganglion cells. 



Fig. 1. Section showing relation of nucleus and sphere. 



Fig. 2. Section showing centrosome and centrosphere with radiations. 



Fig. 3. Section showing in addition flattening of nuclear membrane on the side 



toward the sphere. 

 Fig. 4. Tangential section of body wall to show branching and anastomosing of 



nerves beneath the hypodermis. X 300. 

 Fig. 5. Cross section of nerve cord in the region of the sub-oesophageal ganglion, 



showing the symmetrically placed giant cells and cross sections of the 



two forks of Leydig's fibre. (Drawn by K. Hyashi.) 



