342 KJELLMAN, THE ALGZ OF THE ARCTIC SEA. 
Lithoderma lignicola. Ig. 8—11. 
Fig. 8. Piece of wood covered with the plant. !/,. 
» 9 Part of the basal layer of the frond. 49/). 
» LV. Radical transverse section of the frond. 7°°/,. 
» Il. Horizontal tangential section of the frond. 4/,. 
Dictyosiphon corymbosus f. abbreviata. Ig. 12—15. 
Fig. 12. Older specimen bearing zoosporangia. '/). 
» 13. Part of transverse section of the lower part of the main axis of the frond. 7°°/,. 
» 14. Part of branch, bearing zoosporangia, seen superficially. 10°), 
» 15. Part of transverse section of the same. 7°/,. 
Chorda filum. f. crassipes. ig. 16. 
Fig. 16, Full-grown specimen. 1/). 
Phloeospora pumila. fy. 17. 
Fig. 17. Lower part of the frond with rhizines. %/,. 
PLATE: 27: 
Pylaiella varia. Fig. 1—12. 
Fig. 1. Part of sterile individual. 7°/, 
225 / 
» 2. Zoosporangia developed in different manners. 7*°/;. 
Pylaiella nana. Fiy. 13—15. 
225 / 
Fig. 13. Vegetative part of the frond. °7°/). 
» 14, Part of vertical cell-row bearing two gametangia (zoosporangia multilocularia) one, of which is void. 7?°/;. 
» 15. Parts of vertical cell-rows bearing zoosporangia (?).  ?7°/). 
PLATE 28. 
Monostroma saccodeum. ly. 1—10. 
Fig. 1—2. Young individuals, still cystiform. 1/,. 
» 3—4, Older, full-grown individuals of somewhat different habit.  !/,. 
» 9, Lowest part of the frond, seen superficially. 49/,. 
» 6. Transverse section of the same part. 4°°/;. 
» 7, Part of the vegetative portion of the frond. 49/). 
» §. Transverse section of the same. 49°/,. 
» YJ. Part of the zoosporiferous portion of the frond. 4%/,. 
» 10. Transverse section of the same. 49°/). 
