KONGL. SV. VET. AKADEMIENS IIANDLINGAK. BAND. 20. N:0 5. 99 



Organs of propagation. Conceptacles of sporocarps and sporangia are to be found 

 on the same individual. The former are conical, low, with a canal at the tip, almost 

 as wide at the base as the conceptacles of the sporangia. That part of them which 

 rises above the siirface of the frond, becomes easily detached and falls away at last, 

 whereupon a cup-shaped scar with somewhat elevated edges appears on the surface of 

 the frond. This hollow is gradually filled with new-formed tissue so as to efface the 

 scar. These local new formations contribute to the unevenness of the frond. I have 

 never seen conceptacles of sporocarps with distinct spores. The sporocarpal bed is 

 plane, and the sporigen cell-rows are developed peripherically on it. 



The conceptacles of the sporangia become finally immersed. They are numerous, 

 scattered, large, about 700 ,«. in diameter, much elevated hemispherically. The roof, 

 whose thickness amounts to 125 f^. when the sporangia are ripe, is intersected with 

 numerous, 80 — 90, transversely six-angular canals, whose orifices are surrounded with 

 a ring of cells differing in shape and size from the other surface cells (fig. 2, 3, 6). 

 The sporangia are tetrasporic, cylindrical, cylindrically spindleshaped, or slightly clavi- 

 form, large, 190—220 ,«. long, 50- 100 ^. thick (fig. 7). 



The relation of the present species to others. In sterile condition and superficially 

 considered, the present species may be easily confounded with other crustaceous Litho- 

 thamnia. However, it is sharply distinct from these by its large, strongly prominent 

 conceptacles of sporangia and its coarse structure. 



Habitat. It grows scattered, in company with other Lithothamnia, at a depth of 

 5 — 10 fathoms on stony and gravelly bottom, on open coasts as well as in sheltered 

 places. In June it bears ripe sporangia, on the coast of Norway at the beginning of 

 the month, on the west coast of Novaya Zemlya at its end. The formation of carpo- 

 spores appears to set in earlier. 



Geogr. Distr. This alga belongs to the Atlantic as well as the arctic region of 

 the Polar Sea. Its northernmost known place of growth is Karmakul Bay on the west 

 coast of Novaya Zemlya, about 72° 30' N. Lat. 



Localities: The Norwegian Polar Sea: Tromso amt at Karlso; Finmarken on the 

 south coast of MagerS, everywhere local and scarce. 



The Murman Sea: Karmakul Bay, scanty and local. 



Lithothamnion foecundum nob. 



L. fronde Crustacea, initio arete adnata, demum soluta, circa 2 mm. crassa, in statu juvenili Isevissima, 

 nitida, eetate provectiore conceptaculis sporangiferis insequali, dilute rosea, limbo albido, margine undulato-lobato, 

 6 cellulis majoribus constructa; conceptaculis sporangiferis iramersis, tecto margine elevato circumdato, demum 

 innatis, depresso-globosis, numerosissimis; sporangiis] quaternas sporas foventibus, 120 — 185 j.i. longis, 45 — 66 

 f.1. crassis. Tab. 5, fig. 11 — 19. 



iSyn. Lithothamnion polymorphum Kjellm. Kariska hafvets Algv. p. 15. 



Descriptio7i of the species. Habit. The plant covers stones and other hard objects 

 in the shape of a crust. At first it is fastened closely and firmly to its substratum, 

 but when older is easily separated from it- The form of the crust depends on that of 



