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



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

 Cruoria pellita Harv. Phyc. Brit. pi. 117, but he says that the Ochotsh plant difi'ers 

 in some respects from the EnglisFi one. This accords well with my own observations. 

 The differences between the English-French Petrocelis cruenta and Ruprecht's Cruoria 

 Middendorffii are in my opinion so considerable, that they ought to be regarded as 

 separate species. The alga found by me on the coast of Finmarken differs, just as the 

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

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

 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- 

 PRECHT I. c. 



Habitat. The present species has been found in the Polar Sea growing on rocks 

 and stones between tide-marks 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 Oxfjord at the mouth of Altenfjord. 



Petrocelis cruenta J. G. Ag. 

 Spec. Alg. 2, p. 490. 



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



Fig- » u 1'nuR. in Le Jol. Liste Alg. Cherb. t. 3, lig. 3 — 4. 



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



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

 there are some microscopical preparations of that alga in a sterile condition which, in 

 his list of the alga3 of Nordlanden, he names Petrocelis cruenta. Judging from these 

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

 Middendorffii 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. This 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 exposed coasts as well as in the interior 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 Atlantic region 

 of the Polar Sea. 



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



