Plankton-samples collected in the North Atlantic 

 Ocean (Latitude 57" -60° N.) in 1899, 



l>y Di'. K. J. V. Steenstrup. 



Examined by 

 C. Я. Ostenfeld and Ove Paulsen. 



[Extract of the preceding paper.] 



The samples mentioned in the preceding tables were collected 

 by Dr. Steenstrup on a voyage to Greenland in 1899 by a method 

 invented by himself. He has described the method as follows: — 

 The apparatus used for collecting consists of a brass tube, 30 cm. 

 long, with an opening at its anterior end, about 1 cm. in diameter; 

 the bottom consists of a piece of silk gauze, fastened down by a 

 ring which can be screwed on ; the tube is cylindrical , and has a 

 diameter of 4 cm. In order to keep the Plankton quiet so that it 

 may settle down at the bottom , a brass plate with holes , about 

 3 mm, wide and placed in a circle, is fitted in front of the gauze, 

 and about 1 mm. from it. The apparatus is thus very easy to 

 manage and it can be dragged after the ship like a log. — In 

 order to obtain a complete outline of the Plankton of the North 

 Atlantic Ocean at the time when the voyage was made the appa- 

 ratus was continually dragged after the ship except the few minutes 

 when it was taken up and had the silk gauze changed, which was 

 generally done every four hours. Thus every Plankton-sample does 

 not represent the Plankton of one particular spot, but consists of 

 that taken in the stretch of water between the place where the 

 preceding one was taken and the point in question. The silk gauze 

 with the plankton collected in it was put into a glass containing 

 .spirits. Of such samples 107 were collected on the voyage out, 

 and 69 on the homeward route; they all contain almost exclusively 

 microplankton, as the apparatus hardly ever catches larger organisms. 

 The result arrived at through the investigations of the samples is 



