KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. 20. N:0 5. 335 



Fig. 13. Vertical, tangential thin section, '"'/i. 



» 14. Part of the basal system of the frond in thin radial section. '"'*/i- 



» 15. Part of the thickening system of the frond, ^^^j. 



» 16. Part of horizontal, tangential, superficial thin section. *"%. 



» 17. Section of a part of the frond provided with a conceptacle of sporangia, ""'/i- 



» 18. Part of the roof of a conceptacle of sporangia, delivered from lime, """"/i- 



» 19. Sporangium, '""'/i. 



PLATE 6. 

 LithothamnioD flavescens. Fig. 1—7. 



Fig. 1. Part of frond covering Lithothamion compactum. '/,. 



» 2. Conceptacle of sporangia, seen from above. ^%. 



» 3. Thin radial section with a grown-in conceptacle of sporangia. Of the sporangia only the gelinated 



tips remain. *"/,. 



» 4. Thin radical section of the lower part of the frond, ^'"'/i- 



1) 5. Part of horizontal, tangentical, superficial thin section. *""'/j. 



» 6. Part of the roof of a conceptacle of sporangia, delivered from lime. 



400/ 



'l- 



Lithothamnion compactum. Fig. 8 — 13. 



Fig. 8. Part of a crust-complex with a yonng crust on its surface. Vi- 



» .9. Thin vertical section of an older crust-complex. *%. 



» 10. Part of the basal system of the frond in thin radial section. '"'%. 



» 11. Part of the thickening system of the frond, ^""/i- 



» 12. Part of superficial, horizontal, tangenti.il thin section. *""/]• 



PLATE 7. 

 Rhodomela virgata. 



Fig. 1. First year's plant in summer habit, '/i- 



" 2. First year's plant in autumnal habit. Yi- 



« 3. Part of a branch with stands of sporocarps developed during the winter, '/j. 



» 4. Stand of sporocarps. *%. 



» 5. Stand of antheridia. *%. 



» 6. Stand of tetrasporangia. *"/'- 



» 7. Part of cross section of the main axis of an older plant near the base. *%. 



« 8. Part of median longitudinal section of the main axis of an older plant near the base. **/). 



PLATE 8. 

 Rhodomela subfusca. 



Fig. 1. First year's plant in summer- and autumn-habit. '/,. 

 " 2. First year's plant in winter habit, '/r 



