132 & Foslie. 



in the lower or lowest part of the frond, are long and bran- 

 ched, with the cells 40 — 60 [x thick and their length 5 — 9 

 times the thickness. To the present species I also refer S. 

 Sonderi Ktitz., characterized by its proportionate coarse- 

 ness and rigidity, short cells and fastigiate outline. By the 

 kindness ofFerd. Hauckl have had the opportunity to 

 examine an authentic specimen of S. Sonderi, and to my 

 experience it no doubt may be regarded a form af S. arcta. 

 I also met with it at Finmarken. It closely resembles cer- 

 tain forms of f. typica, differing only with reference to its 

 coarseness and rigidity, in which respects it reminds of f. 

 penicilliformis. A still coarser form is S. hystrix Stromf., 

 formerly only known from Iceland. According to Strom- 

 felt (1. c.) it occurs on the coast of Iceland in ball-shaped 

 specimens floating in the surface* of the water, attaining a 

 diameter of 10 cm. At the coast of Finmarken I found it 

 lying loose on the bottom, forming loosely entangled masses 

 of indefinate shape. However I have collected perfectly sphe- 

 rical balls of S. arcta, most nearly related to the typical 

 form. The Finmarkian specimens of f. hystrix are sparing- 

 ly branched with a thickness of about 200 |x, and the length 

 of the cells varies between Va an d 3 times the diameter. 



The species in question is litoral and sublitoral. In 

 the former case it grows on rocks, wood-works, in rock-pools, 

 or epiphytic on other algee in every part of the zone. In the 

 latter case it descends to a depth of about 10 fathoms, oc- 

 curring on various bottom, either fastened to stones or epi- 

 phytic on other algae, even the leaves of Laminaria digitata. 

 It partly appears scattered partly gregarious, and not sel 

 dom in large masses so as to give the vegetation its cha- 

 racter. It occurs both on open and sheltered coasts, in 

 much exposed as well as sheltered localites. The typical 

 form lives in both the named regions; f. pulvinata I have 

 only seen in the litoral zone, on open coast; f. penicillifor- 



