Lewis. — Nervous Syst. Polychaeta. 



PLATE 6. 



All the figures shown in Plate 6 represent sections through sense organs from 

 Axiothea torquuta stained with methyleii blue. All are drawn to a magnification of 

 750 diameters, with the exception of Figures 37 and 46, which were drawn under 

 a ^j (Zeiss) homogenous immersion lens. 



Fig. 37. Section showing the peripheral portion of the cells drawn in Figure 38, 

 more highly magnified. 



Fig. 44. Section through a sense organ on the ventral side of the worm, showing 

 one cell belonging to the sense organ, and four belonging to the central 

 nervous system (compare Plate 3, Fig. 21, cl. n.). In two cells the 

 nucleus was clearly distinguishable ; in two it was not. The single 

 continuous line farthest from the cuticula indicates the boundary of the 

 fibrous portion of the ventral nerve cord. 



Fig. 47. The line farthest from the cuticula indicates the boundary of circular 

 muscles. 



