KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. 20, N:0 5. 297 
burst at the top, expand and become slit usually in their whole length. The segments 
when fully grown are even 10 em. long, sometimes few in number, being then ovate 
g, in both cases 
or elliptical, sometimes numerous, being then usually lanceolate or oblong 
often repeatedly and more or less deeply divided. The margin of the segments is 
generally wavy or crisp; fig. 3—4. When the frond grows older, it either detaches 
itself altogether from its substratum or else a number of segments are loosened that 
afterwards float on the surface of the water or lie loose on the bottom. These seg- 
ments, after having become free, often increase considerably in size. There are to 
be found pieces which have a length of 15—20 cm. by a breadth of about 10 em. 
When growing older the plant assumes a pale yellowish-green colour. It is loose and 
slimy in consistency so that it adheres strongly to the paper in drying. The lowest 
part of the frond nearest the callus is composed of claviform cells with very gelati- 
nous walls, similar to those of several other species of Monostroma, as JM. arcticwm and 
M. Greville. Their rooms are 6—10 w. thick in their longest diameter. The heads of 
the clubs occupy the middle of the frond, the shafts being placed towards the surface; 
ne. 5—6. 
The rest of the frond is composed of cells with ellipsoidic or ovate rooms, the 
long axis of which is at right angles to the surface of the frond. The whole wall of the 
cell is covered by the chlorophyllous body; fig. 8. Downwards this part of the frond 
is 30—40 wu. thick, the cell-rooms are 15—17 w. high and 8—10 w. in diameter. At 
the upper margin of the frond the thickness is somewhat less, 25—30 w., the rooms 
of the cells are somewhat lower and broader, almost round. The cells containing zoo- 
spores have somewhat thinner walls than the vegetative ones, partition-walls of more 
equal thickness, and somewhat larger rooms; fig. J—10. 
Habitat. This species grows within the litoral zone on exposed coasts, somewhat 
gregarious, but not in great numbers, attached to litoral alge, as Corallina, Rhodo- 
mela lycopodioides, Halosaccion, Fucacee or to serpulids and stones. I have found at 
the beginning of August on the coast of Finmarken fully developed individuals with 
zoospores as well as very young ones scarcely one millimetre in length. 
Geogr. Distrib. It is known as yet only from the north coast of Norway, the 
northernmost point where it has been met with being Gjesver, about Lat. N. 71°. 
Localities: Nordlanden according to specimens in Kriren’s herbarium; Finmarken: 
Maasé local but rather abundant, Gjesver local and scarce. 
Monostroma angicava nob. 
M. thallo callo radicali adnato, initio vesicam pyriformem constituente, deinde expanso, membranaceo, 
flaccido, lubrico, fusco-viride, demum pallescente, parce laciniato, margine plano, lacerato; parte monostromatica 
45—60 «. crassa, cellulis in sectione transversa thalli lumina cellularia verticaliter rectangularia, angulis ro- 
tundatis, 25—28 uw. alta, 8—10 w. lata prebentibus, corpore chlorophylloso cellulas vegetativas non explente. 
Tab. 29. 
Description. The present species is attached by a callus radicalis. It has when 
young the form of a pear-shaped bladder, attaining a length of 5 em. by 4 em. in 
» ’ 
K. Vet. Akad. Handl. Bd 20. N:o 5. 38 
