KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. 20. N:0 5. 319 



agrees more closely with C. N ordenshioldianum than with C. gregarium. Foslie after- 

 wards found the same plant at Finmarken. He detected there yet another Codiolum, which 

 has been described by him under the name of C. longipes and is intermediate between 

 C. gregarium and C. N ordenskioldianum. It resembles C. gregarium in size and with regard 

 to the proportion in length between the club-head and the stipe, C. Nordenskioldianum 

 with regard to the shape of the club-head. After I had described C Nordenskioldia- 

 num, I have also myself found a Codiolum on the coast of Finmarken, which I have 

 distributed under this name in the above-quoted collection of exsiccates. It does not 

 however completely coincide with the Spitzbergen form, being larger than this and not 

 always exhibiting the same proportion as this between the length of the club-head 

 and the shaft. Probably it is to be considered an intermediate form between C. Nor- 

 denskioldianum from Spitzbergen and C. longipes from the north coast of Nor- 

 way. A fourth form of the genus has been lately observed on the north-east coast 

 of North America. According to what Foslie has communicated to me by letter, it 

 may be identified with C. longipes, although it differs somewhat from this. It appears 

 to me to agree more nearly than C. longipes with C. gregarium. It results from 

 these facts that the genus Codiolum has shown itself of late to possess in the northern 

 seas a considerable number of forms that are only slightly differentiated and should 

 possibl)^ be justly regarded as forms of one and the same species. It is evidently a 

 genus in course of developing species. Nevertheless the species distinguished ought 

 to be kept up, until more forms shall have been discovered at other places. This will 

 no doubt happen now, since more attention has been directed to these small and easily 

 overlooked algae. The last finds prove that they are no rarities and have an extensive 

 range on the coasts of the old as well as the new world. In the present work I un- 

 derstand C. Nordenskioldianum as including both the form from Spitzbergen and that 

 from Finmarken. Its length does not in general exceed 600 ,«. The thickness of the 

 club-head usually amounts to 25 — 50 f^., sometimes 70 ,u. in specimens from Finmar- 

 ken. The head of the club is in most cases longer than the shaft, sometimes as long 

 as or somewhat shorter than the shaft, and elongated-obovate in shape. 



Habitat. It forms a thin cover on stones within the litoral zone on exposed 

 coasts, together with Urospora penicilliformis. It is gregarious, occurring in considerable 

 masses. I have found specimens Avith zoospores in July on the north coast of Spitz- 

 bergen, towards the end of August on the coast of Finmarken. 



Geogr. Distrib. Known from the Norwegian Polar Sea and the eastern Green- 

 land Sea. Its northernmost point is Duympoint on the north coast of Spitzbergen 

 Lat. N. 79° 30'. 



Localities: The Norwegian Polar Sea: Finmarken at Maaso, local, but abundant. 



The Greenland Sea: the north coast of Spitzbergen, Duympoint, local, not abun- 

 dant. ') 



') It has been stated by mistake, that the C. Nordenskioldianum distributed under N:o 425 in Alg. Scand. 

 exsicc. has been collected at Insula; Spetsberrjenses. This is not true. It has been taken on the north 

 coast of Norway at Maaso in Finmarken, at the same place and time as the specimens distributed in 

 Wittr. at Nordst. Alg. exsicc. N:o 51. 



