KONGL. SV. VET. AKADEMIENS HANDLINGAR. 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 surface 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 uw. in diameter, much elevated hemispherically. The roof, 
whose thickness amounts to 125 “. 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 wu. long, 50— 100 wu. 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: Tromsé amt at Karlsé; Finmarken on the 
south coast of Mageré, everywhere local and scarce. 
The Murman Sea: Karmakul Bay, scanty and local. 
Lithothamnion foecundum nob. 
L. fronde crustacea, initio arcte adnata, demum soluta, cirea 2 mm. crassa, in statu juvenili levissima, 
nitida, eztate provectiore conceptaculis sporangiferis inzequali, dilute rosea, limbo albido, margine undulato-lobato, 
e cellulis majoribus constructa; conceptaculis sporangiferis immersis, tecto margine elevato cireumdato, demum 
innatis, depresso-globosis, numerosissimis ; sporangiis! quaternas sporas foventibus, 120—185 w. longis, 45—65 
u. crassis. Tab. 5, fig. 11—19. 
Syn. Lithothamnion polymorphum Kse ium. Kariska hafvets Algv. p. 15. 
Description 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 
