JL he Swedish expedition to Greenland in 1899 under the direction of Prof. A. G. Nathorst 

 paid considerable attention to hydrographical researehes. Not only the physical pro- 

 perties and the chemical coniposition of the water were examined, where the vessel 

 »Antarctie» passed, but also a considerable number of samples of plankton were collected, both 

 from the surface and at certain stations from more or less considerable depths. The hydro- 

 graphical work has been carried out by the hydrographer of the expedition Dr. F. Åker- 

 blom, who furnished me with all the hydrographical data mentioned in the following. All 

 the samples of plankton were delivered to me for examination. In carrying out that work 

 I had for some determinations the advantage of the assistance of Prof. G. O. Särs (all 

 schizopoda, some amphipoda and copepoda) and of Mr. Joh. Gunnar Andersson (ostracoda), 

 for which I tender these gentlemen my best thanks. 



i. Samples collected in May. 



The route of the »Antarctie» was from Skagen towards S. Norway, above the deep 

 »Norske Rende» and the 200-metre plateau to midway between Norway and the Shetlands. 



In the Skagerak water of 34,83 to 25,92 p. m. salinity prevailed and contained 

 chiefly tripos-j>la?ikton. Towards Norway and above the deep »Norske Rende» the salinity 

 varied from 23,52 to 34,94 p. m. and contained northern neritic plankton (represented by 

 Chcetoceros constrictus, Lrptocylindrus danicus, Thalassiotlirix Frauenfeldii, Calanus Jin- 

 marchiens and Evadne Nordmannii) besides /r//><>s-plankton. Above the 200-metre plateau 

 there prevailed water of 35 p. m. salinity containing in abundance Phceocystis Pouchetii, 

 thus a facies of Chaito- plankton {Cfi). 



The latter kind of water had a considerable thickness, as is proved by the deep sea 

 hauls made at 61° 16' N. 1° 18' E., which shew that the same kind of water and of plankton 

 occurred at least to the depth of 100 metre. 



The samples contained the species mentioned in Table I. 



Besides there were found some rarer forms, viz: 

 Fritillaria borealis Lohm. 10 +, 11 r. Centropages typicus Kröyer +. 



Oikopleura (dioica Fol.?) 1 ;•, 6 c, 11 ccc. Oithona plumifera BAIRD 18 rr. 



Acartia lonyire)nis Lilljeb. 1 r, 2 r, 8 r. Podon Leuckarli G. O. Särs. 1 r, K) rr, 11 r. 



Centropayes hamatus Lilljeb. 6 +, 8 r. Sagitta bipunctata Quoi & Gaim. 1 r, 6 +. 



