— 377 - 



Gladophora diffusa Stromf. Algveg. p. 55. 



All the specimens in Strtimfelt's collection determined by him as G. 

 diffusa (Roth) Harv. belong to the genus Acrosiphonia. 



Fam. Gomontiacese. 



Goiiiontia polyrhiia (Lagerh.) Born, et Flah., Sur deux nouv. gen. 

 d'Algues perfor. Journ. de Bot. Tom. II, 1888, p. 1G3. 



It occurs most frequently associated with Ostreobium Queketti growing 

 in the old shells of Mya truncata, Astarte, Gyprina islandica, Gardium. 

 Mytilus modiola, Buccinum undatum and Balanus sp. ; it has also been 

 found in species of Lithothamnion. It occurs down to a depth of at least 

 31 fathoms. Probably common. 



E. Icel. ReyOarfjorOur, SeydisfjorOur. 



N. Icel. EyjafjorOur. 



NW. Icel. Hri'itafjorOur, Isafjorflur; D^rafjor^ur (G.O.) ; ArnarfjorOur. 



SW. Icel. Stykkisholmur, Reykjavik. 



Fam. Phyllosiplioiiaceae. 



Ostreobium Uueketti Born, et Flah., Sur quelques plantes vivant dans 

 ie test calcaire des mollusques p. 15, pi. IX, fig. 5— 8. 



This species occurs associated with Gomontia polyrhiza in old shells 

 of Mya truncata, Astarte, Gyprina islandica, Gardium, Mytilus modiola, 

 Buccinum undatum and Balanus sp. It has also been found in species 

 of Lithothamnion. It has been dredged down to a depth of 13 — 24 

 fathoms. Probably common. 



E. Icel. Vattarnes, Holmanes. 



N. Icel. EyjafjorOur. 



NW. Icel. HrutafjorOur, IsafjorQur; Dfrafjovbm (G. 0.). 



SW. Icel. Stykkisholmur, Reykjavik. 



