incompletely calcified cells are dissolved away daring the process. 

 Zeiss. 4 X AA. 



14. A diagramatic figure of a cross section of an articulus ; the boundary 



between the cortical layer and medullary part is shown with a dotted 

 line. Zeiss 2 x AA. 



Fiîïs. 15 — 10. Amphiroa ecJiigoensis. 



15. A portion of a longitudinal section of an articulas bearing a conceptacle : 



the cortical cells are arranged in the anticlinal direction forming a 

 thick layer. Zeiss. 4 x BB. 



16. A diagramatic figure of the cross section of an articulas, compare with 



Fig. 14. Zeiss. 2 x AA. 



Figs^ 17 — 21. Amphiroa dilatata, Lmnx. 



17. Diagramatic figure of a meridional section of a fertile articulus, with 



numerous conceptacles. Zeiss. 2 x AA. 



18. A part of the same magnified. The periclinal cells are interwoven like 



a mat. From a fresh material. Zeiss. 4 X BB. 



19. A part of the cross section of an old genicuium. Zeiss. 4 X DD. 



20. A longitudinal section of the same : transverse thickenings of the walls 



are highly developed, with connecting canals between newly formed 

 intercellular spaces. Zeiss 4 X DD. 



21. An upper portion of a frond, showing zonal arrangement of the 



periclinal cells ; the space bounded with a dotted line indicates the 

 genicular area ; this area stains metachromatically with some stain- 

 ing reagents after decalcification. Zeiss 2 x AA. 



Figs. 22 — 28. Amphiroa pusilla. 



22. A cross section of a frond through a conceptacle ; from a fresh material. 



Zeiss. 2 X BB. 



23. A diagramatic figure of a cross section of an articulus. 



Figs. 24—25. Aviphiroa misal-iensis. 

 24 and 25. Diagramatic figures of the cross sections of the articuli. 



