IX 



'uriiig the years 1898 and 1899 a, large number of samples of plankton have been 

 collected from all parts of the Atlantic Ocean by Dutch, English and French ocean liners, 

 by some wessels of the Dutch and Swedish navy, by whalers in the Arctic Sea and 

 besides, at some stations, viz. at Vestmanna 6 (S. Iceland), tlie Faroes and the Azores. 

 Most samples of plankton were collected at the same time as the temperature of the sea 

 was determined and samples of water for the determination of the salinity preserved. 

 Professor S. 0. Pettehsson and M. Gust. Ekman have charged themselves with 

 the purely hydrographical work and left to me the examination of the plankton. In 

 examining these samples I found a number of forms, which seem to me to be new to 

 science, and some, the determination of which seems to me to be uncertain for the 

 want of figures in the litterature. As I intend to publish in a future work my notes 

 on the seasonal distribution of the Atlantic plankton-oi'ganisms as well as an account of 

 the mean and extreme temperature and salinity for every species, I wish here to publish 

 my drawings of some new or doubtful forms. 



Although the officers on many of the ocean liners and government wessels have 

 assisted us in a most liberal way for this extensive hydrographical and biological survey of 

 the Atlantic, still considerable expenses ha\'e been necessary. For covering these we 

 have obtained from the fund 'Lars Hiertas Minne the sum of 7,000 kroner. 



I. COPEPODA. 

 Acartia niacropus. N. Sp. 



I'hitu I. Fig. 1 7. 



Male. Length of cephalothorax 0,88, of abdomen 0,3, of furca, 0,u.), of the longest 

 seta of the furca 0,4. Breadth of cephalothorax 0,24 millim. 



Lateral angles of the last segment of the thorax rounded; margin of the last seg- 

 ment smooth, without small spines. 



Rostral filaments present. 



i?. e. 2 of the right fifth foot longer than broad; K. e 3 elongate, with a very small 

 terminal claw. 



