KONGL. SV. VET. AKADEMIENS IIANDLINGAK. BAND 20. N:0 5. 333 



Explanation of the figures. 



PLATE 1. 

 Lithothamnion soriferum. 



Young specimen, '/i* 



Somewhat older specimen, seen from above, '/j. 

 The same specimen, seen from below, '/j. 

 Full-grown specimen. Vi- 



Half of a younger specimen, seen from the cleaving^surface. '/,. 

 -10. Branch-systems of different development. Vi- 

 Branch with conceptacles of sporangia, '■'/j. 

 Part of transversal thin section') of a branch, '"/j. 

 Part of median thin section of a branch. *%. 



Part of one of the outer concentric layers of a transversal thin section, '""/i. 

 Part of the central layer of a transversal thin section. *""/!. 

 Part of a superficial tangential thin section. **"'/i. 



Part of the roof of a conceptacle of sporangia, delivered from lime. *"%. 

 Sporangium. '"*%■ 



PLATE 2. 



Lithothamniou glaciale. 



Fig. 1. Older, full-grown specimen, seen from above. Yi- 

 » 2. The same, seen from below. Vi- 



PLATE 3. 

 Lithothamniou glaciale. 



Fig. 1. Young specimen, surrounding part of a stone. Vi' 

 » 2. Somewhat older specimen, completely inclosing a stone, '/i- 



') Thin section = slice made thin by grinding. 



