274 С. H. Ostenfeld. 



res, 1905, p. 118, PI. 15, figs. 8 d, e) has found Ch. criophihim in the 

 antarctic ocean with aborted awns. He tells that the chains of this 

 abnormal aspect occur in depths of 100 — 80 m. and supposes that 

 the phenomenon is connected hereto: „Darin ist eine Minderung 

 des Formwiderstandes gegeben , . . Diese Zellen resp. Zellreihen 

 schweben dementsprechend in tieferen Wasserschichten; . . . ." But 

 this explanation does not hold good in our case where the abnormal 

 chains occur in the surface layers of the water. 



D i strib. ЛУ1ае1у distributed species of northen Oceanic character, 

 known from all Oceans. 



24. Chaetoceras decipiens Cleve, Bib. K. Svenska Vet. Akad. 

 Handl., Bd. I, No. 13, 1873, p. 11, pi. 1, fig. 5; Gran, Norske Nordhavs- 

 Exp., Protophyta. 1897, p. 13, pi. 1, figs. 2—3, pi. 3. fig. 34; Fauna 

 Arctica, HI, Heft 3, 1904, p. 535, pi. 17, figs. 1—6; Nord. Plankton XIX, 

 p. 74, fig. 88. 



As C. boréale one of the most common species in the area. It 

 was rather rare in the pack-ice both in 1906 and in 1908, but domi- 

 nant in both years in the whole series of samples from the coastal 

 water (July— August) and in 1908 in Danmarks Havn. At the last 

 named place it was also observed in October 1906, some of the fru- 

 stules being empty, and in July— September 1907, but not in larger 

 quantities. It seems thus as if the species has its real place of thriving 

 in our area in the coastal water between the coast and the pack-ice. 

 In a number of samples, especially in the samples from July 1908 

 the terminal awns had the peculiar structure which is characteristic 

 for С Lorenzianum Grun.; and also in the coarser awns from the 

 other cells of the chains the structure was discernible, but more 

 difficult to see. In other respects the specimens were quite typical, 

 e. g. the awns being coherent at a part of their length, the terminal 

 awns making the curvature at their proximal ends and then slightly 

 divergent or nearly parallel. It is then not possible to refer our 

 specimens to С Lorenzianum Grun., nor to the arctic species C. mitra 

 (Ehrbg.) Cleve. More probably a closer examination of the coarser 

 specimens of С decipiens from other regions will result in finding 

 the same structure of the awns. 



Besides this observation, another matter of some interest was 

 found : 



In two samples from August 1906 and in two from July 1908 

 I have found microspore formation in the cells. All these samples 

 have been taken in the ice-filled coastal water north of 77° N. Lat. 

 the temperature of the water being between -^ 0,5° and 1,4°. The 

 examination of this microspore development does not give much 



