DIATOJIACE^ — THALASSIOSIRA ri;):) 



Aii(ju.vt: (if)'- N. 36° W., rare. 

 1899 AJay: HK^ N. 22- W., not rare; 75- N. 2- 80' E., rare. 



Temperature: l.s, mean of 1- obs., max. 5 min. ■ — 1. 

 Salinity: 34.59, mean of 4 obs., max. 34.9a, min. .31. ^u. 

 Plankton-type, Noted from the E. and W. (Jreenland. ^- 



Xu (T). 



THALASSIOSIRA NORDENSKIOLDII Cl.i 

 (Van Heiri;iv Syn. PI. LXXXIII iig. 9) 



1898 Man-lr, 40 N. 69" W., rare; 10' N, US' W., common; 42- N. 

 51° W. to 42- N. 42' W., common; 58' N. 6" E , rare, 

 April: S. and W. of Iceland, not rare; Faroes, rare. 



Maif. 72- N. 14° W. to 70^ N. 15' W.. not rare; N. of Iceland, 

 common; Westmannao, not rare; Faroes, common; 59 N. 

 49' W. (common) to 63- N. 54- \V , not rare. 



Juiw: 67- N. 21' W. to 65 N, 29'— 31° W., common; West- 

 mannao; Cape Farewell to 69'' N. 54' W.; Faroes, rare. 



Aiif/iisr: Faroes, rare; 65° N. 3() W„ rare. 



Si'pti'iabcr: 69° N. 53 \V., rare. 



1899 Apfil . Faroes, rare to common. 



May: Westmannao, rare; Faroes, not rare; 61° N. 1" W., 



common; 60- N. 2- 30' E., rare; 75 N. 2- yjO' E., rare. 

 Ji(/ic: 75- — 78" N. 20'— 12" E., rare. 

 July: 80' N 14' E., rare. 

 Sciih'inhcf: 80 N. 13' E., rare. 



Temperature: 7.4 max. 16, min. l.s. Only such samples con- 

 sidered as contained this species abundantly. 



Salinity: 34.53, mean of 11 obs. max. 36. n min. 31.98. 



Plankton-type. Typical arctic species. Its occurrence on the 

 driftice at Cape Vankarema seems to proves that it occurs in the 

 Polar Basin whence in drifts along the coasts in the Arctic regions. 

 I have seen it in samples from Hudson Bay and from the northern 



' Ostenfeld's data used. 



