DIATO.MACKK — RHIZOSOLF.N'IA 341 



Tempepatupe: 15.7, mean of "iH obs., max. 27.3, min. 7. 

 Saltiiity: 35.36, mean of 24 obs., max. 36.33, min. 32.9G. 

 Plankton-type. Occurs in plankton from Jedo Bay, Japan. — N. 



RHIZOSOLENIA CYLINDRUS Cl.' 

 (A Treatise on the Phyto-plankton PI. II fig. 12). 



1897 December: and 



1898 January: 12° N. oO' W.; Caribbean Sea; 25" N. 74" W. 

 February: Caribbean Sea. 



March: 3° N. 24^ W. 

 April: 10° N. 53° W. 

 May: Caribbean Sea; 41° N. otr W. 

 July: 24° N. 54° W.; 4(;)- N. 67—58- W. 

 August: 40° N. 66° W. to 42° N. 50° W. 

 September: 9" N. 53° W.; Caribbean Sea. 

 October: Caribbean Sea; 34° N. 74° W. 

 December: Caribbean Sea. 



Tempepatupe: 25.3, mean of 20 obs., max. 28. j, min. 19.8. 



Salinity: 34.95, mean of 13 obs., max. 36.3s, min. 33.2o. 



Plankton-type. This species lias been seen once in the Guinea 

 Current; else it seems confined to the sea along the north coast of 

 South America, the Caribbean Sea and Florida Current. In July, 

 August it follows the Desmo-plankton between 67° — 50° W. beyond 

 t(i° X. The low mean salinity indicates it as a more neritic than 

 oceanic form. Schroder mentions it from Naples. — Nt (of the 

 western Atlantic). 



RHIZOSOLENIA DELICATULA Cl. 



(Kongl. Sv. Vet. Akail. Handl. Vol. XXXII n. 8 pag. 28). 



1898 March: 58° N. 6° K. 

 Any u St: Azores. 



TempepatuPBi 6 to 23.7. 



Ostenfeld's data not used. 



