591 



and, according lo their biogeographical relation put them together 

 inlo gronps, which, borrowing a term from plant-geography, Gran 

 calls elements. 



Gran and the aulhor of this paper have in several treatises 

 described many snch plankton-associations (»Genossenschaf- 

 ten«). They appear at Ihe same place and al alinost fixed seasons 

 of the year — the one association succeeding the other, just as the 

 plant-associations on land, c. g. in a wood, change according lo the 

 season of the year, but a plankton -association is not confined to 

 any particular geographical locality because the ouler conditions of 

 lifc, such as light, warmth, salinity and nutritive matter may be the 

 same in different piaces and that, consequenlly, makes it possible 

 for the same plankton -association to thrive in different piaces. It 

 is naturally enough impossible to draw any very narrow limits for 

 such associations, the faet that some species, which olherwise belong 

 to an association, are wanting in a locality where the other charac- 

 teristic species occur, does not entitle one to establish a new associa- 

 tion ; it is much better to take them in as wide a sense as possible. 



In what follows an attempt will be made on the strength of 

 the samples examined to describe the plankton -associations which 

 occur along the Færoes. To attain to as much clearness as possible, 

 the samples have been divided into two groups, viz. 1. Samples 

 taken in the Atlantic Ocean in the vicinity of the Fær- 

 oes, i. e. samples which will often be found to have an oceanic 

 character; and 2. Samples taken in Nolsofjord off Thors- 

 havn or in the neighbourhood of it. The reason why the latter 

 have been separated is, partly, because there is a long continuous 

 row of samples from this particular locality, and partly, because 

 the neritic forms are much more conspicuous in these samples 

 gathered near land than in the others. In Ihe aeeompanying 

 tables I have placed the common forms together. The tables are 

 arranged in conformity with the usual plankton-tables, in which 

 the frequency is indicaled as follows: - — cc (main part of the 

 planklon), c (predominanl), + (rather common), r (rare), rr (very 

 rare, only a few specimens seen); but lo avoid making the lists 

 too long and conlusing I have — as Cleve also in his laler 

 works — omitted those forms which only occur in a few of the 

 samples and usually in small quantities; the laller forms are enume- 

 rated directly after the tables and prefixed with Ihe same number 

 as that of the samples. 



