KONGL. SV. VET. AKADEMIENS HANDLINGAK. BAND. 20. N:0 5. 141 



1. C. by RuPRECHT. He compares it — and he is quite justified in doing so — witli 

 Cruoria pellita Harv. Phyc. Brit. pl. 117, but he says that the Ocliotsh plant differs 

 in somc respects from the Englisli one. This accords well witli rny own observations. 

 The difterences between the English-French Petrocelis cruenta and ri,UPRECHT's Cruoria 

 Middendorfjii are in iny opinion so considerable, that they onght to be regarded as 

 separate speeies. The alga found by me on the coast of Finniarken difters, just as tlie 

 Ochotsh form, from the niore southern Petrocelis cruenta by a more strongly developed 

 basal layer, by the vertical cell-rows being often branched, and, above all, by the difie- 

 rent shape and position of the tetrasporangia. In P. cruenta these are developed above 

 the middle of the vertical cell-rows. Cp. Le Jolis Liste Alg. Cherb. t. 3 and Ru- 

 PKECHT 1. c. 



Habitat. The present speeies bas been found in the Polar Sea growing on rocks 

 and stones between tide-raarks on exposed coasts. Here it has young tetrasporangia in 

 course of development in September. 



Geogr. Distrib. Within the Polar Sea it is known only from the north coast of 

 Norway. Its only certain Locality is Öxfjord at the mouth of Altenfjord. 



Petrocelis cruenta J. G. Ao. 

 Spec. Alg. 2, p. 490. 



Desor. Petrocelis cruenta J. G. Ag. 1. c. 



Fig- M « 'J"huk. in Le Jol. Liste Alg. Cherb. t. 3, (ig. 3 — 4. 



Syn. Petrocelis cruenta Kleen, Nortll. Alg. p. 14. 



Remark on the determination of the speeies. In Kleen's collections from Nordlanden 

 there are sorae microscopical preparations of that alga in a sterile eondition which, in 

 his list of the algaa of Nordlanden, he names Petrocelis cruenta. Judging from these 

 preparations, this plant seems really to be another speeies of Petrocelis than the P. 

 Middendorfjii occurring on the coast of Finmarken. But on the other hand I am un- 

 able to decide with certainty whether the plant from Nordlanden is identical with the 

 P. cruenta occurring on the coasts of France and England, or with the P. Ruprechtii 

 common on the western coast of Sweden. Tliis cannot be decided by means of ste- 

 rile specimens. Accordingly I think I ought to adhere to the determination made 

 by Klen. 



Habitat. The present alga grows, according to Kleen, on rocks between tide- 

 marks on e.xposed coasts as well as in the interiör of bays. Only sterile specimens 

 are known from the Polar Sea; they were collected in summer. 



Geogr. Distrib. It is known only from the southern part of the x4tlantic region 

 of the Polar Sea. 



Localities: The Norwegian Polar Sea: Nordlanden, common and abundant. 



