Marine Plankton from the East Greenland Sea. 279 



as the treatement given by Lemmermann (Arkiv f. Botanik, Stock- 

 holm, Bd. 2, No. 2, 1904) is not a good one. 



D i strib, (of Ch. gracile, sens, lat.): Euryhaline neritic species known 

 from coasts of Greenland and Europe. 



Biddulphia Gray, 1831. 

 31. Biddulphia arctica (Brigtw.) Boyer, Proc. Acad, of Nat. Sc, 

 Philadelphia, 1900, p. 714; Gran, Nord. Plankton, XIX, 1905, p. 109, 

 fig. 143; B.balœna Brightw., Quart. Journ. Microsc. Sc, vol.8, 1859, 

 p. 181, pi. 9, fig. 15; Triceratium arcticum Brightw.. ibid, vol. 1, 1853, 

 p. 250, pi. 4, fig. 11. 



Found sparingly in three samples from Danmarks Havn, Aug.— 

 Septm. 1907. 



Distrib. Littoral form (not true plankton form) from the Arctic coasts. 



B. Pennatæ. 



Fragilaria Lyngb., 1819. 



32. Fragilaria islandica Grun. in V. Heurck, Synopsis, 1883, 

 pi. 45, fig. 37 ; Jørgensen, Bergens Museums Skrifter 1905, p. 102, pi. 6, 

 fig. 10; Gran. Nord. Plankton. XIX, 1905, p. 114, fig. 153. 



Only found in Danmarks Havn, where it was present in the 



plankton, although only scattered, in all three years. July — October. 



Distrib. Arctic neritic species, known from the coasts of the European 

 Arctic sea; probably not a real plankton form. 



33. Fragilaria oceanica Cleve, Bih. K. Svenska Vet. Akad. Handl., 

 Bd. 1, No. 13, 1873, p. 22, pi. 4, fig. 25; Grunow, Diat. v. Franz Josefs 

 Land. 1884, p. 55, pi. 2, fig. 14; Gran, Bibliotheca Botanica, Heft 42, 

 1897, p. 20, pi. 1, figs. 6—9; Nord. Plankton XIX, 1905, p. 114, figs. 

 154-155. 



In 1906 only very few samples contained this species, and only 

 in few specimens, while in 1907 and 1908 it was a dominant feature 

 in July and August samples from Danmarks Havn and the coastal 

 water. In the pack-ice it was not at home, recorded in few speci- 

 mens from three samples (two in 1906 and one in 1907). July — 

 October. 



Several of the forms distinguished by Gran (1905) according to 



the curvature and twisting of the chains, were seen. In all samples 



from 1907 and 1908 resting spores were present, often in large 



quantities. 



Distrib. Arctic neritic species known from Davis Strait and the 

 Euopean Arctic Sea and a little more southwards. 



