560 



plankton of the open Ocean« and »the floating Fauna and Flora 

 of the coastal regions« ; the same author (1. c. p. 25) distinguishes 

 also belween holoplanktonic and meroplanktonic organisms, 

 i. e. organisms which spend their whole life as freefloating indivi- 

 duals, and organisms which spend onc part of their life floating as 

 plankton, and the other part as bottom organisms. The two latter 

 terms are sharper and clearer than Ihe two former, but it has be- 

 corne customary to use the former so that they are almost identical 

 with the latter; it must, however, be remarked that while all the 

 oceanic species are holoplanktonic and the greater part of the neritic 

 species are meroplanktonic, it is possible that some of the neritic 

 species are holoplanktonic, at any rate our present knowledge of 

 the life-history of these minute organisms is not so complete that 

 we can preclude this possibility 1 . 



The plankton of the North Atlantic Ocean and its tributaries 

 have d uring the last 10 years become fairly well-known through 

 the researches of different (especially Scandinavian) investigators 2 , 

 and therefore, as was to be expected, only a few new forms were 



1 Cfr. H. H. Gran: Hydrographic-biological Studies of the North Atlantic 

 Ocean and the Coast of Nordland. — Report on Norwegian Fishery- and Marine 

 Investigations. Vol I. No. 5. 1900. Kristiania, p. 27. 



H. H. Gran: Das Plankton des Norwegischen Nordmeeres, von hiologischen und 

 hydrographischcn Gesichtspunkten behandelt. — Ibidern, Vol. II, No. 5. 1902. Bergen. 

 This very important treatise came in to my hånds while I was writing the present paper.) 



2 P. T. Cleve: Plankton collected by the Swedish Expedition to Spitzbergen 

 in 1898. — Kongl. Svenska Vetenskaps Akademiens Handlingar. Bd. 32, No. 3. 

 Stockholm, 1899. 



P. T. Cleve: Report on the Plankton collected bj' the Swedish Expedition to 

 Greenland in 1899. — Ibidern, Bd. 34, No. 3. 1900. 



P. T. Cleve: Notes on some Atlantic Plankton-Organisms. Ibidern, Bd. 34. 

 No. 1. 1900. 



P. T. Cleve: Karakteristik af Atlantiska Oceanens vatten pa grund af dets 

 mikroorganismer. — Ofversigt af K. Sv. Vetensk. Akad. Forhandl. 1897, No. 3. 



P. T. Cleve: On the seasonal distribution of some Atlantic plankton Or- 

 ganisms. — Ibidern, 1899, No. 8. 



P. T. Cleve: On the origin of »Gulf-Streamwater«. Ibidern, 1899, No. 9. 



P. T. Cleve, G. Ekman, O. Pettersson: Les variations annuelles de l'eau 

 de surface de l'Océan Atlantique. — Goteborg 1901. 



P. T. Cleve: A Treatise of the Phytoplankton of the Atlantic and its Tribu- 

 taries and on the periodical changes of the Plankton of Skagerak. Upsala 1897. 



George Murray: Observations on Plant Plankton. — Journal of Botany, 

 Vol. XXXV, 1897, pj). 387— 395. 



E. Vanhoffen: Die Fauna und Flora Gronlands. — Gronland-Expedition der 

 Gesellscliaft fur Erdkunde zu Berlin 1891—93. — Vol. II, Parti, 1S97. 



C. H. Ostenfeld: see note on p. 558. 



