MARINE ALGAL VEGETATION 57 



With respect to the 6 species (A, 9 14) which have been found 

 only in N. Iceland, it cannot be assumed that they are confined to 

 the north coast, and it is highly probable that they have a much 

 wider distribution on both sides. Dictyosiphon corymbosus and Ulo- 

 thrix consociata v. islandica must, however, be assumed to belong 

 more closely to E. and N. Iceland. 



/ 



As regards the 8 species (A, 15 22) which occur so far west 

 or south as NW. Iceland or SW. Iceland, it must be supposed that 

 their absence from N. Iceland (and E. Iceland [Ceratocolax, CruoriaJ) 

 is due merely to insufficient knowledge regarding their distribution. 

 Of these species, those which extend to SW. Iceland have not been 

 found, however, further south than in Breidifjordur, with the ex- 

 ception of Peyssonellia which has been found in Faxafloi near 

 Reykjavik. 



Of the species given under A, Nos. 1 8, 12 and 14 23 must 

 consequently be supposed to have an east-northward distribution 

 along the coast of Iceland, while Nos. 9, 11 and 13 must be sup- 

 posed to have some other principal distribution; one species (10) is 

 endemic in the most western part of the north coast. 



Under B, 53 species are recorded. Of these 10 have been found 

 only in S. Iceland , the majority of these in the Vestmannaeyjar 

 only; to these must be added Bonnemaisonia (31, p. 141) which I 

 believe to have been found in S.Iceland. That is, 11 species in all, 

 one of which, however, Rhodochorton repens, is endemic. 17 species 

 have been found only in S. and SW. Iceland (B, 1228) and 8 species 

 in SW. Iceland only. Thus, there are in all 36 species which are 

 known from S. and SW T . Iceland only. 6 species (B, 37- -42) have a 

 more northern distribution, as they have been found in NW. Ice- 

 land. Consequently, there are 42 species which are known only 

 from S. and W. Iceland (NW. Iceland included), but of these species 

 there are two, Cladophora rupestris and Codiolum Petrocelidis which 

 probably have a more northern distribution. 10 species (B, 43 52) 

 which have principally a south-western distribution (the fact that 

 some of them have not been found in NW., SW. and S. Iceland is 

 probably due to insufficient knowledge regarding their distribution) 

 have been found also in N. Iceland. But all these species do not 

 reach eastward along the north coast to the same extent, Ptilota 

 plumosa and Corallina officinalis have been found furthest east in 

 the eastern part of the north coast; Lithophyllum Crouani and 

 Myrionema vulgare in Eyjafjor5ur; Ahnfeltia and Peirocelis extend to 



