Plate VI. 



Transverse sections of the body-wall figs, i, 3, 5 in the region of the oesophagus; figs. 2, 4 in the cnido- 

 glandular tract of the filaments, fig. 6 in the hyposulcus region (Magnification 4/ 3 Reichert's "Austria"; 

 the figures drawn on the level of the microscope's foot; fig. i same magnification but with drawn out 



tube. Entoderm not drawn in figs, i 4). 



Fig. i of Isozoanthus bulbosus (from Ingolf Exp. St 104). 



2 - arborescens (from Mortsund, Nordgaard). 



3 - multinsulosus (from Ingolf Exp. St. 51). 



4 - magninsulosus. 



r 



5 



6 - ingolfi (from Ingolf Exp. St. 27). 



