296 KJELLMAN, THE ALGiE 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 fi. 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 fi. thick; the rooms of the cells being 10 — 15 ,". 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 tlie frond the vege- 

 tative cells, as seen from the surface, are 4 — 5-angular with thick walls. Their longest 

 diameter is about 20 — 25 fi.\ 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 f^. 

 in diameter, with very thick walls. The rooms in cross section are either circular or 

 circular-elliptical with their long axis, 17 — 22 fi., parallel to the surface of the frond; 

 fig- 6-7. 



Habitat. This species is litoral, attached to other algte, especially Halosaccion 

 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 Gjesva;r about Lat. N. 71°. 



Localities: Fin mark en at Maas6 and Gjesvser, local and scarce. 



Monostroma saccodeum nob. 



M. thallo callo radical! adnato, initio saccato, deinde membranaeeo, in lacinias oblongas, lanceolatas vel 

 ovatas, raargine vel crispo plus minus decomposito-fisso; parte monostromatica inferne 30 — 40, superne 25 — 30 

 u. crassa, a cellulis constructa a fronte visis luraina rotundata; semicircularia vel 3 — 5 angulata inter se mem- 

 lirana crassiusoula separata, in sectione transversa thalli visis lumina cellularia verticaliter elliptica 15 — 17 f.t. 

 alta, 8 — 10 lata priebentibus; corpore chlorophylloso lumen cellulare fere omnino explente. Tab. 28, fig. 1 — 10. 



Syn. Monostroma latissimum Kleen, Nordl. Alg. p. 41; saltern ex parte fide herb. 



Description. The present species agrees with M. GrevilLei 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 pj'^riformly 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 



