Plate III. 



Fig. 19. Pliobothrus symmetricus; median longitudinal section of a branch point. l6 /!. 

 20. median section through a gasteropore with tabula. l6 / t . 



21. Stylaster gemmascens; median longitudinal section of a branch. l6 / t . 



22. roseus; median longitudinal section of a branch. l6 / t . 



23. norvegicus; longitudinal section through two cyclosystems. l6 / r . 



24. Median, longitudinal, thin section of the gasterostyle in Stylaster gemmascens. 9/ x . 



25. Longitudinal section of the gasterozooid in Stylaster gemmascens. ^o/j. 



26. Transverse section of the gasterozooid at the base of the tentacles in Stylaster gemmascens. 3/, 



27. Oblique transverse section of the gasterozooid at the base of the tentacles in Stylaster 



norvegicus. ^/ I . 



28. Transverse section of the gasterozooid in Pliobothrus symmetricus. ^/ I . 



29. Longitudinal section through the oral part of the gasterozooid wall in Pliobothrus symme- 



tricus. 45/j. 



30. Longitudinal section through the oral part of the gasterozooid wall and tentacle in Stylaster 



gemmascens. 45/ r . 



31. Longitudinal section through oral part of the gasterozooid wall and tentacle in Stylaster 



norvegicus. 45/j. 



