282 с. H. Ostenfeld. 



41. Nitzschia seriata Cleve, Vega Exp. vetensk. iaktl., Bd. 3, 1883, 

 pi. 38, fig. 75; Gran, Nord. Plankton, XIX, 1905, p. 129, fig. 174; Л^ 

 fraudulenta Cleve, 15. Ann. Rep. Fishery Board for Scotland, part III, 

 1897, p. 300, flg. 11; Synedra Holsatiæ Hensen, 5. Ber. Komm. Uniers. 

 Deutschen Meere, 1887, p. 91, pi. 5, fig. 50. 



Only found in Danmarks Havn (Aug. 1907, July 1908) in four 



samples, but mostly rare. 



Di strib. Widely distritjuted in open seas and along the coasts, pro- 

 tjably a neritic species of northern, but not arctic cliaracter. 



42. Nitzschia delicatissima Cleve, A Treatise of Phytoplankton, 

 1897, p. 24, pi. 2, fig. 22; Gran, Nord. Plankton, XIX, 1905, p. 130. 



Found together with the preceding species in two samples from 

 Danmarks Havn, Aug. 1907. 



D ist rib. Mucli like the preceding, but more restricted. 



Nitzschiella Rabenh., 1864. 



43. Nitzschiella closterium (Ehrbg.) Rabenh., Fl. Europ. Algar., I, 

 1864, p. 163 ; Ceratoneis closterium Ehrbg., Kreidethierchen, 1840, p. 64, 

 pi. 4, fig. 7; Nitzschia closterium W. Smith, Syn. British Diatoms I, 

 p. 42, pi. 15, fig. 120; Gran, Nord. Plankton, XIX, 1905, p. 129, fig. 172. 



Found together with the preceding in two samples from Dan- 

 marks Havn (Aug. 1907) and further in one sample from the coastal 

 water (July 1908); a littoral species which sometimes occurs in 

 plankton as it often inhabits mucilage of other organisms. 



Distrib. Ubiquitous along the coasts. 



