Plate III. 



Fig. 19. Pliobollirus symiiutricus\ median longitudinal section of a branch point. "Vi- 



— 20. — — median section through a gasteropore with tabula, "^/j. 



— 21. Stylastcr geiiiiiiasccns\ median longitudinal section of a branch. '7i- 



— 22. — roseus; median longitudinal section of a branch, "'/j. 



— 23. — )iorvegicus\ longitudinal section through two cyclosystems. '^/j. 



— 24. Median, longitudinal, thin section of the gasterostyle in Stylaster gciiimasccns. 9"/i. 



— 25. Longitudinal section of the gasterozooid in Stylaster gciiimascens. '3oyj. 



— 26. Transverse section of the gasterozooid at the base of the tentacles in Stylastcr giiiiinasccns. 300/j 



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



norvegic2cs. =°°U. 



— 28. Transverse section of the gasterozooid in Pliobothrus syiiiiiictricus. 3oo/j. 



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



tricns. 45o/j. 



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



gcmmascens. 45°/,. 



— II. Longitudinal section through oral part of the gasterozooid wall and tentacle in Stylastcr 



norvegicus. 450/j. 



