294 



In the table the stations are indicated by Roman numerals and the number 

 of the haul by Arabic. The other points are self-explanatory. 



The twenty-one stations are quite widely distributed, as the accompanying 

 map will show, so as to include as many of the various conditions as possible. 

 To see whether local variations ati'ect the distribution of plankton, two or more 

 hauls were made at the same station as nearly under the same conditions and in 

 as quick succession as possible. Following Apstein, the mean for the hauls thus 

 made is taken, and the per cent, of variation of each haul from this mean is cal- 

 culated. The results are shown in the following table : 



Thus 9 hauls vary between .12 per cent, and 5 per cent. ; 12 between o.l and 

 10; 7 between 10.1 and 15; 4 between 15.1 and 20, and 5 between 20.1 and 25; 

 1 haul varied 25.1 per cent. 



