PLATE XLI. 



FIG. I. Spirorbis violaceus Levinsen, p. 242. Collar seta from specimen from 

 the Grand Banks, Atlantic Ocean. 



2. Another collar seta. 



3. Spirorbis verruca (Fabricius), p. 247. Collar seta showing slight pos- 



terior notch in margin, from specimen on Chlamys islandicus from 

 Greenland. 



4. Spirorbis asperaius sp. nov., p. 245. Collar seta (serrations too dis- 



tinctly marked). 



5. Abdominal seta, back view. 



6. Collar seta of another specimen (serrations invisible). 



7. Spirorbis eximius sp. nov., p. 239. Seta from second thoracic segment 



of specimen from Pacific Grove, California. 



8. Spirorbis asperatus sp. nov., p. 245. Curved shaft associated with ab- 



dominal seta. 



9. Spirorbis sulcatus (Adams), p. 249. Collar seta from specimen on 



Haliotis from Guernsey, England. 

 10. Spirorbis asperatus sp. nov., p. 245. Abdominal seta (no serrations), 



profile view, 

 n. Apparent arrangement of teeth on uncini, greatly enlarged. 



12. Spirorbis verruca (Fabricius), p. 247. Another collar seta showing but 



very slight indication of posterior notch. 



13. Spirorbis semidentatus sp. nov., p. 237. Capillary seta from thorax. 



14. Spirorbis vitreus (Fabricius), p. 247. Collar seta from specimen from 



the Banks, Atlantic Ocean. 



15. Spirorbis morchi Levinsen, p. 240. Caudal seta from Alaska speci- 



men, back view. 



16. Another, in profile. 



17. Spirorbis semidentatus sp. nov., p. 237. Caudal seta. 



18. Spirorbis eximius sp. nov., p. 239. Collar seta. 



19. Spirorbis asperatus sp. nov., p. 245. Uncial plate from thorax, about 



f view. 



20. Spirorbis eximius sp. nov., p. 239. Odd seta from third thoracic 



fascicle. 



21. Spirorbis morchi Levinsen, p. 240. Collar seta from specimen on 



Chlamys islandicus from Greenland. 



22. Spirorbis formosus sp. nov., p. 251. Caudal seta from specimen from 



Bermuda. 



23. Spirorbis semidentatus sp. nov., p. 23^. Another caudal seta. 



24. Spirorbis morchi Levinsen, p. 240. Seta from third thoracic fascicle 



of Alaska specimen. 



25. Collar seta from same specimen. 



26. Spirorbis semidentatus sp. nov., p. 237. Seta from second or third 



fascicle. 



(340) 



