DIATOMACEyE — STREPTOTHECA, THALASStOSIRA 353 



STREPTOTHECA THAMESIS Shrubs. 

 (Cl. A Treatise on the Phyto-plankton PI. II flg. 19.) 



1898 January: 48° N. 6° W. 

 March: 4o° N. 36° W. 

 April: 58° N. 2° W. 



1899 March: 48° N. ()° W. 

 April: 50° N. (>" W. 



Temperatupe: in.o, mean of 5 obs., max. 13 min. 8. 



Salinity: 35.52. 



Plankton-type. This species occurs in the southern North 

 Sea, in the mouth of the river Tliames, at the coasts of Scotland, 

 but in the Atlantic only occasionally. The above mean salinity it 

 therefore to be considered as anomalous. — Xm. 



THALASSIOSIRA GELATINOSA (Hexsex), 

 (A. Schm. Nord Sea Diat. PI. XXXVIII fig. 3.) 



1898 April: 63° N. 18° W., common. 



1899 June: 69' N. 13' W.; 6.') N. 1° W. (deep sea haul from 200 



to m.). 



Temperature: 7. 



Salinity: 26.5 1. 



Plankton-type. Found in the Arctic Sea, the North Sea 

 and the Skagerak. It occurs also in the northern Pacific (between 

 Vancover Island and British Columbia, Lemmermaxa). — Nfj. 



THALASSIOSIRA GRAVIDA Gl.^ 



(Bih. Kongl. Sv. Vetensk. Akad. Handl. Vol. XXII 3 n. 4 PI. 11 lig. 14—16. — Gran. 

 ,I». Norske Nordhavs Exped. 1876-78 Protophyta PI. IV lig. 57—58.) 



1898 March: 74° N. 5° W., rare; 58° N. (>" E; Faroes, rare; 40° N. 

 68°— (59° W. 

 April: 66° N. 24° \\'., common; S. of Iceland, not rare; Far- 

 oes, rare; W. of the Shetlands, rare; 42' N. 17° W. and 

 40° N. 68° W., rare. 



Ostenfeld's data used. 



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