PLATE XL. 



Fig. I. Spirorbis ahnormts sp. nov., p. 245. Front view of calcareous plate 

 from operculum of a young specimen. 



2. Side view of same. 



3. Hyalofomatopsis occidentalis sp. nov., p. 229. Abdominal seta. 



4. Spirorbis variabilis sp. nov., p. 238. Caudal seta. 



5. Spirorbis spirorbis (Linne), p. 262. Collar seta of specimen from 



Gloucester, Massachusetts, back view. 



6. Odd seta from third thoracic fascicle, about % view. 



7. Spirorbis spirillum (Linn^) var. /««'<^«5 (Montagu), p. 243. Caudal 



seta of specimen from Pacific. 



8. Spirorbis spirorbis (Linn^), p. 262. Entire seta from one of a chain 



of embryos taken from tube. 



9. Spirorbis similis sp. nov., p. 242. Collar seta. 



10. spirorbis quadrangularis Stimpson, p. 241. Collar seta of specimen 



from Greenland, about % view. 



11. Curved abdominal seta. 



12. Spirorbis spirorbis (Linn^), p. 262, Collar seta from another 



specimen. 



13. Seta from second or third thoracic fascicle. 



14. Side view of odd seta from third thoracic fascicle. 



15. Caudal seta. 



16. Spirorbis marioni Caullery and Mesnil, p. 239. Collar seta of specimen 



from Mexico. 



17. spirorbis similis sp. nov., p. 242. Back view of operculum of a young 



specimen, showing calcareous plate. 



18. Front view of same. 



19. Spirorbis incongruus sp. nov., p. 241. Front view of calcareous plate 



from operculum. 



20. Back view of same. 



21. Spirorbis quadrangularis Stimpson, p. 241. Seta from second or 



third thoracic fascicle, in profile. 



22. Hyalopomatopsis occidentalis sp. nov., p. 229. Collar seta, basal fin 



much spread. 



23. Spirorbis quadrangularis Stimpson, p. 241. Collar seta of specimen 



from the Banks, Atlantic Ocean, 



24. Spirorbis granulatus Linn6, p. 247. Collar seta of specimen from the 



Banks, Atlantic Ocean. 



25. Spirorbis sp. Collar seta. 



26. Spirorbis quadrangularis Stimpson, p. 241. Base of collar seta (blade 



broken) from specimen from Greenland. 



27. Spirorbis cancellatus Fabricius, p. 248. Collar seta. 



28. Spirorbis ificongruus s^^. nov., p. 241. Collar seta. 



29. Spirorbis stimpsoni Verrill, p. 250. Odd seta from third thoracic 



fascicle. 



(338) 



