298 KJELLMAN, THE ALG^ OF THE ARCTIC SEA. 



diameter upwards. This bladder opening at the top and bursting down to the base, 

 the frond expands and in its further growth becomes irregularly laciniate. A full- 

 grown specimen with zoospores in my| collection is almost reniforra in outline, with 

 the margin lobed and slashed, but not crispy. The alga in its younger condition is 

 dark green in colour with a brown tinge, but when older it becomes more pale. It 

 has no gloss and is slimy and loose in consistency; fig. 1. 



The lower part of the frond is composed of club-shaped cells extending in an 

 oblique direction from one surface of the frond down to the other. The heads of the 

 clubs are elongated, obovate, cylindrical or fusiform, often curved; fig. 2 — 3. The 

 steril, monostromatic part of the frond is 45 — 50 n. thick, composed of slender and 

 high cells. A transverse section of the frond shows the rooms of the cells to be ver- 

 tically rectangular with much rounded corners. Their height is about 25 fi. by 8 — 10 

 ,«. in breadth. The endochrome does not fill the whole cell-room; fig. 4 — 5. 



I have found the part of the frond bearing zoospores 55 — 60 ,«. thick, with the 

 cell-rooms 25 — 28 ,«. high and usually 10 f^. broad; fig. 6 — 7. For other particulars 

 the reader is referred to the figures cited. 



The present species belongs to the same group of the genus Monostroma as the 

 two preceding, M. arcticum and \£. Grevillei a. o. It cannot be confounded with any 

 species that has been before described, being easily distinguished from all by its nu- 

 merous and high cell-rooms and the thick walls of the cells. 



Habitat. At the place where it was found by me, it grew within the litoral re- 

 gion in an exposed locality on litoral alg«. At the beginning of August it was pro- 

 vided with zoospores. 



Locality: It is known as yet only from the Norwegian Polar Sea, where I have 

 found some few specimens at MaasO in Finraarken. 



Monostroma Grevillei (Thue.) Wittr. 



Monostr. p. 57. Enteromorpha Grevillei Thur. Note s. Ulv. p. 25. 

 Descr. Monostroma Grevillei Wittr. 1. c. 

 Fig. » » » t. 4, fig. 14. 



Exsicc. » » Wittr. et Nordst. Alg. exsicc. N:o 434. 



Syn. Monostroma Grevillei Gobi, Algenfl. Weiss. Meer. p. '79. 

 » » Kleen, Nordl. Alg. p. 41. 



Habitat. This species lives rather gregarious, on exposed coasts, attached to stones 

 within the litoral zone or lying loose on the bottom in the upper part of the sublitoral 

 zone. Individuals collected by Kleen at Nordlanden in June and at the beginning of 

 July are furnished with zoospores. 



Geogr. Distrib. It belongs only to that part of the Polar Sea which lies imme- 

 diately to the north of the Atlantic. Its maximum of frequency is on the north-west 

 coast of Norway. The most northerly place where it has been found is Hammerfest 

 Lat. N. 70° 40'. 



