EXPLANATION OF PLATES. 



Plate III. 



All the figures are niicrophotoj>raphs after microtome-sections taken by Mr. A. Hesselbo. 



1. Litholhaminon keve Stromf. Tetraspore (dispore), showing the nucleus with nucleolus 

 (fallen out) and the structure of the protoplasm. (Specimen from Aalsgaarde). About 225:1. 



2. Litholhainnion Lenormandi (Aresch.) Foslie. Vertical section of antheridial conceptacle. 

 (Specimen from TF'). About 200:1. 



3. Lithotharnnion Lenormnndi (Aresch.) F"oslie. Vertical section of conceptacle of cy,stocarp. 

 (Specimen from XQ). About 200:1. 



4. Lithotharnnion glaciate Kjellm. f (iranii Fosl. Section of crustaceous frond with con- 

 ceptacles of sporangia. Specimen from L8es0 Rende). About 180 : 1. 



5. Lithotharnnion polifmorphnni (L.) Aresch. Vertical section of female conceptacle showing 

 procarps. S])ecimen from Store Middelgrund, May). 



6. Litholhainnion potginorphnm (L.) Aresch. Vertical section of emptied conceptacles of 

 sporangia with covering tissue. (Specimen from reef near Korser). 



Plate IT. 



AH ligures from photo]jra])hs in natural size. 

 —4. Lithotharnnion gtaciale Kjellm. f. Granii Fosl. 1 and 2 attached to stones, 3 free, 4 



similar one being on the point of dividing. (Specimens from IH, 3375). 

 —6. (loraltina of/icinalis L., f. robusta Kjellm. (Specimen from YU, Hanstholm. 7286). In fig. 



5 the branchlets are partly verticillate. 



7. Coratlina of/icinalis L., slender, slightly branched form with some stoloniform branches 

 growing out in a transversal direction. (Specimen from UC, north of Lseso, 5625). 



8. Coratlina of/icinalis L. f. robusta Kjellm. With lateral -conceptacles. (Specimen from 

 MZ, 4058). 



