106 L. KoLDERUP Rosenvinge. 



This species has been found growing on Phyllophora Brodiæi 

 *interrupta, Delesseria sinuosa and Lithoihamnion glaciale. The speci- 

 mens were 1 to 2 cm. long, all sterile. 



Loc. Danmarks Havn and the entrance to it. 



Rhodochorton Næg. 



10. R. Rothii (Turt.) Næg. 



к. Rosenvinge (1893) p. 791, (1898 I) p. 23, Jonsson (1904) p. 8. 



This species has been found in two different sublittoral localities 

 in up to ca. 40 meters depths; it was here mostly found in com- 

 pany with Craoria arctica, forming scattered tufts on the surface of 

 the latter. A closer examination showed however that, at all events 

 in some cases, it had grown through the crust of Cruoria, the basal 

 layer being situated under the crust. This has probably been occa- 

 sioned by the Cruoria overwhelming the Rhodochorton growing pre- 

 viously on the stone. This supposition is supported by the fact that 

 the same Rhodochorton was found growing on Lithoihamnion lœve 

 covering the stone beside the Cruoria. These specimens were all 

 sterile. 



Fertile specimens with ripe and empty sporangia were found in 



September in company with Calothrix scopulorum a. o. in a gathering 



from the littoral region. 



Loc. Along Koldewey Island; Vestre Havnenæs, in the tidal region; off 

 Baadskæret and along Vestre Havnenæs, ca. 40 meters. 



11. R. penicilliforme (Kjellm.) К. Rosenv. 



к. Rosenvinge (1894) p. 66, (1898 I) p. 23, Jonsson (1904) p. 9. 

 R. mesocarpum (Carm.) Kjellm. var. penicilliforme Kjellm., K. Rosenvinge (1893) 

 p. 792. 



One specimen of this easily recognizable species was found on 

 Polysiphonia arctica; the upright filaments were 10 // thick and bore 

 young sporangial branchlets but without sporangia. 



Loc. Along Koldewey Island, ca. 8 fathoms. 



Fam. Rhodomelaceœ. 

 Rhodomela G. Ag. 



12. R. lycopodioides (L.) Ag. f. tenuissima (Rupr.) Kjellm. 



K. Rosenvinge (1893) p. 797, (1898 I) p. 24, Jonsson (1904), p. 9. 



This species is only feebly represented in the collection. At 

 Koldewey Island, where it was collected by dredging in September, 

 it occurred in small quantity among Stictyosiphon tortilis; the speci- 

 mens had still hairs (trichoblasts), branched and unbranched, but 



