No. 3] REMARKS ON NORTHERN LITHOTHAMNIA. 2 1 



Area: Norway: From the north-eastern boundary (Magero 

 and Karlso, Kjellmann!) as far south as Balstad in Lofoten (!); 

 N. and E. Iceland (Jons son!); Spitzbergen, west coast: Between 

 Norskoerne and Amsterdamoen (Nils John sen!); Novaia Zembla, 

 west coast: Karmakulbay (Kjellmann!). 



4. Lithothamnion foecundum Kjellm. 



N. Ish. Algfl. (1883), p. 131, t. 5, fig. 11 — 19! Fosl. Norw. Lithoth. (1895), 

 p. 109; Rev. Syst. Surv. Melob. (1900), p. 12; Rosenv. Deux. Mem. Alg. Mar. 

 Gronl. (1898), p. 1 2 ! Jonss. Mar. Alg. led. I (1901), p. 153! De Toni, Syll. Alg. 

 IV (1905), p. 1739. 



Syn : Lithothamnion polymorphum Kjellm. Kariska Hafv. Algveg. (1877), p. 15. 



As to the structure of this species I will only add to the 

 description given by Prof. Kjellm an that I have found the hy- 

 pothallic cells in a vertical section being of a length of up to about 

 four times the breadth, or 15 — 25 or up to 35 /j. long and 7 — 12 /* 

 broad. The perithallic cells are squarish, 7 — 1 1 ;j- in diameter, or 

 vertically elongated and up to 15 /* long, frequently however 

 shorter. Thus the alga in all essentials corresponds with Lithoth. 

 Iceve in structure ; but new crusts are often developed above others, 

 so as to form at last rather thick crustlayers. Besides the con- 

 ceptacles of the species in question become gradually overgrown; 

 which is never the case with Lithoth. Iceve, which therefore, shows 

 a more regular anatomic structure. 



The conceptacles of sporangia are densely crowded over the 

 whole frond except a narrow peripherical portion, 400 (300) — 600/* 

 in diameter, frequently about 500 /*. They are immersed to sub- 

 immersed, at first convex or nearly hemispherical, however by and 

 by decorticated in the central part of the roof. Here they finally 

 become concave or sometimes much impressed, with a border 

 rather strongly elevated, which in fact represents the peripherical 

 portion of the roof. The said central part is traversed by 40—60 

 muciferous canals. The sporangia are four-parted, 120—185 ;j. 

 long and 45 — 90 /* broad. Sometimes the sporangia seem to be 

 two-parted, but such ones perhaps represent organs not fully 

 developed. Besides I have seen very few conceptacles of cysto- 



