Ward. — Sipunculus. 



PLATE II. 



Fig. 15. Transverse section of epithelium of tentacular fold to show the leucocytes 

 in situ. Hamann's carmine. Zeiss 1. E. X 500. 



" 16-18. Sense papillae from anterior papillate zone of introvert. 



" 16. Tangential section through a single papilla. Hamann's carmine. Zeiss 

 1. D. X 300. 



" 17. Transverse section. Apical area retracted. Hamann's carmine. Zeiss 

 1. D. X 330. 



" 18. Transverse section. Papilla fully expanded. Orth's picro-litho-carmine. 

 Zeiss 1. D. X 220. 



" 19. Lateral sagittal section of brain at point of departure of the anterior com- 

 missure from the central fibrous mass. Plane of section indicated on 

 Figure 22 by dotted line " 19." Mayer's cochineal. Zeiss 1. A. X 50. 



" 20. Median sagittal section of brain. Plane of section indicated on Figure 

 22. Mayer's cochineal. Zeiss 1. A. X 50. 



" 21. Cells of tentacular epithelium isolated by maceration ; a, c, and e, sensory, 

 b, d, andy, filamentous cells. Zeiss apochr. 4 mm. Oc. 8. X 725. 



" 22. Central nervous system. Composite figure from maceration preparations 

 controlled by serial sections. The splanchnic nerve («. spl.) should 

 project /o?- ware/ under the brain. For the sake of clearness it is repre- 

 sented as if turned posteriad ; * denotes inferior muscular branch (?). 

 The numbers denote the planes of sections represented in Figures 19, 

 20, 24, and 25. X 8 (about). 



