ÖFVBRSIGT AF K. VETENSK.-AKAD. FÖRHANDLINaAR 1899, N:0 8. 793 



November. S. of Iceland, abundantly. From 56^ N. 30^ 

 W. (abundant) to 53° N. 49° W. 



December. From 48° N. 40° W. to 41° N. 66° W., where 

 it was abundant. 



It seems from the above Statements tbat this species has 

 the same distribution as other species of the tricho-planktontype, 

 more especialiy as the Chcetoceros atlanticiai. It does not go so 

 far south in the winter as other species. It enters, like the 

 preceding the tricho-plankton of the Bering Sea, and its raaxi- 

 mam of abundancy seems to be S. of the entrance to the polar 

 basin. 



Rhizosolenia semispina Hensen in 1898. 



January. Very sparingly S. of the Azores. 



March. W. of Ireland (48° N. 18° W. and 53° N. 20° 

 W.). — From the English Channel to the NW. of the Azores, 

 or from 48° N. 6° W. to 40° N. 21° W. — From 43° N. 45° 

 W. to 40° N. 71° W. 



April. N. of Jan Mayen (73° N. 5° W.). — Not rare in 

 the Färöe Channel. — From 60° N. 19° W. to 59^ N. 30° W. 



— Rare at the south end of Greenland. From 44° N. 40° W. 

 to 40° N. 70° W. 



May. More or less sparingly from 78° N. 2° 30' W. to 

 68° N. 21° W. and between S. Iceland and Scotland. Abun- 

 dantly at the Shetlands. — Abundant from 61° N. 23° W. to 

 the S. of Greenland, rarer in Davis Strait at 63° N. 54° W. 



— From 45° N. 41° W. to 41° N. 54° W. — At 38° N. 21° 

 W. and 49° N. 23° W. 



June. From N, of Iceland into the Denmarks Sound, or from 

 69° N. 15° W. to 65° N. 31° W., not abundant. — From the 

 S. of Iceland to Scotland. — W. of Norway, at 62° N. 2° 30' 

 E. — Davis Strait from Cape Farewell (abundant) to 66° N. 

 55° W. (rare). — At 45° N. 41° W. and 41° N. 58° W. 



July. Rare at 61° N. 6° W. and abundant at 57° N. 

 47 W. 



