74 



H. JONSSON 



resemblance is increased, as it is highly probable that other species 

 which are not common would be simultaneously found. 



From the coast of Norway I select Finmark for comparison 

 with Iceland, which comparison gives the following figures: — 



Iceland 143 species Finmark 125 species 



not common common not common 



45 (26%) 98 (58°/o) 27 (16%) 



A comparison between Finmark and SW. Iceland gives the 

 following figures : — 



SW. Iceland 115 species Finmark 125 species 



not common common not common 



29 (19 %) 86 (56 %) 39 (25 %) 



The following are the 45 species which are found in Iceland 

 and are absent from Finmark: — 



1 Porphyropsis coccinea. 



2 Chantransia Alarise. 



3 Phyllophora membranifolia. 



4 Ceratocolax Hartzii. 



5 Lomentaria rosea. 



6 L. clavellosa. 



7 Plocamium coccineum. 



8 Delesseria Baerii. 



9 Bonnemaisonia asparagoides. 



10 Pterosiphonia parasitica. 



1 1 Gallithamnion Arbuscula. 



12 Ceramium acanthonotum. 



13 C. fruticulosum. 



14 C. arborescens. 



15 C. atlanticum. 



16 Rhodochorton minutum. 



17 R. repens. 



18 Dilsea edulis. 



19 Petrocelis Hennedyi. 



20 Cruoria arctica. 



21 C. pellita. 



22 Rhododermis parasitica. 



23 Petroderma maculiforme. 



24 Ralfsia ovata. 



25 R. clavata. 



26 R. verrucosa. 



27 Myrionema Lamimarise. 



28 M. Corunnse. 



29 M. globosum. 



30 M. fseroense. 



31 Ascocyclus islandicus. 



32 Microsyphar Polysiphoniae. 



33 Ectocarpus Stilophorse. 



34 E. tomentosoides. 



35 E. tomentosus. 



36 E. Hinksise. 



37 Sphacelaria radicans. 



38 S. olivacea. 



39 Omphalophyllum ulvaceum. 



40 Litosiphon filiformis. 



41 Phaeostroma pustulosum. 



42 Phyllitis zosterifolia. 



43 Dictyosiphon Mesogloia. 



44 Desmarestia ligulata. 



45 Laminaria faeroensis. 



Of these species ten (Nos. 3, 6, 7, 10, 11, 12, 18, 21, 26 and 35) 

 are known from Nordland and therefore might possibly be found 

 also in Finmark. Furthermore, nine of the species (Nos. 2, 5, 9, 25, 

 33, 34, 35, 40, 44) are known from West Norway, and the majority 

 of these will also be found, without doubt, in Nordland and Fin- 



