Al^ae. 621 



'■b 



make ihe work accessible for readers not lamiliar with the Danish 

 language. 



Ps-S mentioned in the resume and in corrections and additions, 

 a species of Coccolithophoridae described under the name of Acan- 

 thoica trlspinosa and figured , was during the printing of the work 

 published by H. Lohmann as ^. acanthifera Lohm., which name 

 has priority. Author's abstract. 



l 



Ostenfeld., C. H., The Plankton Work of the Interna- 

 tional Investigation oftheSeain theyears 1902 — 



1912, in: C. F. Drechsel: Memoire sur les travaux 

 du Conseil permanent international pour l'ex- 

 ploration de la mer pendant les annees 190 2 — 

 19 12. (Conseil perm. intern, p. l'explor. de la mer, Rapports et 

 Proces-verbaux des reunions. XVI. p. 42 — 55. Copenhague, Dec. 



1913. Also in german.) 



This Short report contains a summary of the plankton recher- 

 ches carried out during the years 1902—1912 by the different coun- 

 tries which take part in the international Cooperation for the study 

 of the sea. Among the results of this comprehensive work the 

 following may be quoted: 



1. We are now in possession of a knowledge, which is in the 

 main sufficient, with regard to the distribution and occurrence of 

 most of the plankton organisms in the greatest and most important 

 part of the area investigated, viz. The Channel, the North Sea, 

 the Skager Rak, Kattegat and the Baltic; our knowledge is less 

 accurate as regards the plankton of the Norwegian Sea, the 

 Faroe — Shetland Channel and the open ocean west of Ireland 

 and between Iceland and the Faroes, as well as of the Mur- 

 man Sea. 



2. The investigations have also furnished valuable contributions 

 to the knowledge of the seasonal distribution of the plankton orga- 

 nisms. In this respect the different species ma}^ be placed together 

 in certain groups, besides their return 3'ear after year in almost 

 the same order, certain species being most frequently found at the 

 same time. 



3. An annual alternation of flowering periods during which the 

 plankton is very rieh in quantity with periods of decline, is pecu- 

 liar to coastal waters, in contrast to the open ocean waters where 

 the quantity of the plankton never attain such heights. 



4. The later investigations have shown that in order to obtain 

 a füll knowledge of the quantity of the plankton, it is necessary to 

 employ different collecting methods, viz. wide-meshed and fine- 

 meshed silky nets, filtration and centrifugation; only by combining 

 the results obtained b\' these methods it is possible to find the total 

 quantity of plankton present in a given place at a give time. In 

 this respect much yet remains to be done. 



5. It has been shown that the distribution of plankton organisms 

 can be of importance in a hydrographical regard, as an aid to 

 determination of the currents' direction. Organisms of Atlantic ori- 

 gin are carried with the Atlantic water northward round Scotland 

 into the North Sea, even into the Skager Rak, or go in a more 

 north-easterly direction from the Faroe-Shetland Channel over 

 towards the coast of Norway. Organisms from the southern part 

 of the North Sea follow the current northward along the western 



