ÖFVERSIGT AP K. VETENSK.-AKAD. FÖRHANDLINGAR 1899, N:0 8. 787 



November. More or less rare from S. Iceland to the Färöes. 

 — In the Atlantic at 48° N. 29° W., 56° N. 23° W., 51° N. 

 20° W., mixed with species of the trieho-tyi)e. — Not rare on 

 the Newfoundland banks and along the American coast, from 

 48° N. 40° W. to 40° N. 68° W. 



December. Rare S. of Iceland to Scotland. — Frora 47° 

 N. 45° W. to 41° N. QQ° W. 



It is apparent from the above statements that the Chaito- 

 ceros decipiens is distributed from the Channel between Jan 

 Mayen and East Greenland to Iceland. Thence it foUows two 

 lines, one to the SE. and one to the SW. The south-eastern 

 line runs above the Wywille-ridge to the Shetlands and West 

 Norway as well as into the North Sea. The south-west line 

 goes from Iceland to East Greenland, into Davis Strait and 

 from the Newfoundland banks along the American coast. These 

 routes are exactly those which the tricho-plankton takes. The 

 difFerence consists in the fact that the chceto-plankton reaches 

 an enormDus development in the northern Atlantic during the 

 spring, which the tricho-plankton does not. 



It is remarkable that the ChcBtoceros decipiens occurs along 

 the east coast of America only during the winter and the spring, 

 but this is easy to explain. As I shall show in another paper, 

 the water with plankton from the temperate and tropical Atlantic 

 (the styli- and desmo-plankton) expands to the North during the 

 summer and covers the cold, south-going current along the east 

 of America. During the autumn or winter it gets driven away, 

 and then the Chcetoceros decipiens comes to the surface. 



Another very remarkable fact is that the same species 

 occurs during the winter and spring in many spots from New- 

 foundland to the north of the Azores as well as from the south 

 of these Islands to the English Channel and at Cape Finisterre. 

 It is not found in this area during the summer. That it had 

 been conveyed in November from Newfoundland to 20° W. 

 by a surface-current cannot be admitted. The only acceptable 

 explanation is, that the water from the cold current along 



