TUBIFEX. 397 



Plate I, 



Figs. 1 to 3. Diagrammatic representation of the first 

 eighteen segments of the body with the 

 principal organs in each segment, as they 

 appear in the living worm. 



Plate II. 



Fig. 4. Longitudinal section through the prostomium 

 and first six segments of the body to show the 

 anterior part of the alimentary canal and 

 nervous system, x 160. 



Fig. 5. Section through one of the dorsal setigerous 

 sacs, x 510. 



Fig. 6. Isolated setae from dorsal and ventral bundles, 

 x 300. 



Fig. 7. Transverse section through the first segment of 

 the body, showing the buccal cavity and 

 brain. x 200. 



Fig. 8. Transverse section through the first segment, 

 showing brain, peripharyngeal connectives 

 and sub-pharyngeal ganglion. x 200. 



Plate III. 



Fig. 9. Transverse section through segment 8 in the 

 region of the hearts. x 1G0. 



Fig. 10. Transverse section through segment 11, 

 showing the ovaries and one spermatheca. 

 x 100. 



