866 P, T. CLEVE, ON THE ORIGIN OF »GULF-STREAM WATER». 



September. Betweeu 56^ N. 28^ W. and 57^^ N. 14° W. 

 From the south of Iceland (60^—63° N. 26^—25^ W.) to the 

 Shetlands (60° N. 1° 50' W.). North of Iceland, 66° 20' N. 

 18° 30' W. The Färöes. 



October. From the south of Iceland, 63° N. 18° W., 

 to 59° N. 3° W. and thence to 58° N. 32° W. and 56° N. 

 29° W. 



November. From the South of Iceland, 63° N. 19° W., 

 to the Färöes and the Shetlands, 60° N. 3° 33' W. Along 56° 

 N. from 23° to 36° W. 



This diatom is, as it would seem from the above data, an 

 excellent drift-body indicating the courseofthe »gulf-stream water» 

 frora the Azores to Iceland and by way of the Färöe Channel 

 into the North Sea. It follows, like other species of the styli- 

 plankton, the gulf-stream water to the north side of Iceland. 



Challengeria xiphodon Hkl. 



1897 December. The Azores, from 34° N. 30° W. to 41° 

 N. 22° W. 



1898 January. Cape Verde and the Canaries. 

 Mar eh. Cape Verde and at 32° N. 32^ W. 

 April. NW. of the Azores, 41° N. 19° W. 

 July. The Färöe Channel, 62° N. 0° 20' W. 

 September. North of Iceland, Q6^ N. 18° W. 

 November. West coast of Africa, 34° N. 10° W. The 



Azores. Many spots on the space between 53° N. 50° W., 47° 

 N. 40° W., 56° N. 23° W. and 55° N. 14° W. 



December, The Azores and at 42° N. 16° W. 



1899 January. At 45° N. 49° W. 

 February. At 34° N. 40° W. 

 March. At 36°— 37° N. 29°— 26° W. 



This, on the whole a rare, radiolarian thus spreads from the 

 region of Cape Verde to the Azores and to Iceland, which Island it 

 goes round in September, and to the Färöe Channel. The sudden 

 abundancy in November between 53° and 55° N. is remarkable 



