Plate III. 



F"ig. 19. Pliobothrus symmetricus; median longitudinal section of a branch point. l6 /.,. 



— 20. median section through a gasteropore with tabula. l6 /j. 



— 21. Stylaster getnmascens\ median longitudinal section of a branch. i6 /l 



— 22. rose/is; median longitudinal section of a branch. l6 / r . 



— 23. norvegicus; longitudinal section through two cyclosystems. l6 /\. 



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



— 25. Longitudinal section of the gasterozooid in Stylaster gemmascens. I i°/ 1 . 



— 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. 3°°/ lP 



— 28. Transverse section of the gasterozooid in Pliobothrus symmetricus. 3 o/ t . 



29. Longitudinal section through the oral part of the gasterozooid wall in Pliobotlirits syiiune- 



tricus. 450/j. 



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



gemmascens. 45<y T . 



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



norvegicus. 45°/,. 



