THE ANA'l'OMY OF SOALIBREGMA INrLATHiM. 



237 



The Anatomy of Scalibregma inflatum, 

 Rathke. 



By 



J. H. Asliwortli, D.Sc, 



Lecturer on Invertebrate Zoology in tlie University of Edinburgh. 



With Plates 13—15. 



Contents. 



PAGE 



1. Introduction ....... 238 



2. Historical Account ....... 239 



3. Distribution and Habits ...... 240 



4. External Characters : Segnicniation, Apertures, Size, Colour . 242 



5. Parapodia: Cirri, Glands of Cirri ..... 246 

 G. Setffi . 249 



7. Skin 252 



8. Musculature . . . . . • .253 



9. General Anatomy of the Internal Organs .... 254 



10. Coelom 256 



11. Alimentary Canal ....... 256 



12. Vascular System ....... 259 



13. Gills 262 



14. Central Nervous System: Brain, Oesophageal Connectives, Nerve- 



cord ........ 263 



15. Sense-organs: Prostomial Epithelium, Nuchal Organ, Cirri, Seta; . 269 

 10. Lateral Sense-organs . . . . • .270 



Occurrence of Lateral Sense-organs in other Polychseta . 274 



Morphology of Lateral Sense-organs of Polychseta . . 276 



17. Nephridia 280 



18. Reproductive Organs ...... 284 



19. The Family Scalibregmidse ...... 286 



20. Affinities of the Scalibregmida; ..... 297 



21. Summary of Results ...... 300 



22. Literature ........ 303 



