296 KJELLMAN, THE ALG OF THE ARCTIC SEA. 
same time, but becoming only very slightly, if at all, lobed. The frond when bearing 
zoospores has a length of 15 cm. by an almost equal breadth in its upper expanded 
part; fig. 1. 
Its lowest part is formed by club-shaped cells with very gelatinized membranes, 
by the shaft-ends of which it is attached. The club-heads are fusiform, fusiform- 
cylindrical, almost cylindrical, elongated-ovate, their cell-rooms being 5—10 «. in cross 
section at their thickest part. In a transverse cut the club-heads are usually seen to 
occupy one side of the frond, the shafts being placed on the other. This part of the 
frond is 30—40 wu. thick; fig. 2—3. 
At a distance of two millimetres from the callus the frond becomes monostromatic, 
being formed here as well as farther upwards, as far as it is sterile, by cells the 
rooms of which are four-angular in cross section with acute or rounded corners. They 
are sometimes square, sometimes rectangular, in the latter case usually having their 
greatest length in a parallal direction to the surface of the frond. The monostromatic 
part is 40—45 w. thick; the rooms of the cells being 10—15 w. high, the wall is 
accordingly of considerable thickness. The chlorophyl takes up sometimes the whole 
room of the cell, sometimes only a part of it. In the middle of the frond the vege- 
tative cells, as seen from the surface, are 4—5-angular with thick walls. Their longest 
diameter is about 20—25 w.; fig. 4—5. The part of the frond bearing zoospores is 
composed of cells the rooms of which are circular as seen from the surface, 10—17 u. 
in diameter, with very thick walls. The rooms in cross section are either circular or 
circular-elliptical with their long axis, 17—22 ., parallel to the surface of the frond; 
fig. 6—7. 
Habitat. This species is litoral, attached to other alge, especially //alosaccion 
ramentaceum, growing scattered on exposed coasts. Specimens with zoospores have been 
collected at the end of July and the beginning of August. 
Geogr. Distrib. Known only from the Norwegian Polar Sea. Here it is scarce. 
Its northernmost point is Gjesver about Lat. N. 71°. 
Localities: Finmarken at Maasé and Gjesvier, local and scarce. 
Monostroma saccodeum nob. 
M. thallo callo radicali adnato, initio saecato, deinde membranaceo, in lacinias oblongas, lanceolatas vel 
ovatas, margine vel crispo plus minus decomposito-fisso; parte monostromatica inferne 30—40, superne 25—30 
u. crassa, e cellulis constructa a fronte visis lumina rotundata; semicircularia vel 83—5 angulata inter se mem- 
brana crassiuscula separata, in sectione transversa thalli visis lumina cellularia verticaliter elliptica 15—17 uw. 
alta, 8—10 lata preebentibus; corpore chlorophylloso lumen cellulare fere omnino explente. Tab. 28, fig. 1—10. 
Syn. Monostroma latissimum Kueen, Nordl. Alg. p. 41; saltem ex parte fide herb. 
Description. The present species agrees with M. Greville: in development, and is 
related to it even in habit, although in structure the two plants are sharply distinguished. 
The frond when young has the shape of an ellipsoidic or pyriformly cylindrical sack 
or bladder, even 4 cm. in length, of a light grass green colour, almost without gloss, 
with smooth wall, and attached by a callus radicalis; fig. 1—2. These bladders soon 
