326 bulletin: museum of comparative zoology. 



though certainly not neritic, is not oceanic in the true sense, because 

 most of its records are from the neighborhood of land, not from the 

 high seas, in marked contrast to A. okeni. 



Quantitative hauls in the Gulf of Maine. 



Quantitative hauls were made at fourteen of the Gulf of Maine 

 stations; and they are directly comparable with one another because 

 the interval of time between the first and last haul was so short (six 

 days) that they can be considered as practically simultaneous. The 

 volumes of plankton under each square meter of sea area, calculated 

 from them were: — 



These volumes are not the absolute amounts actually present, 

 because they take no account of the coefficient of filtration of the nets. 

 This, however, would be the same for all the hauls, and with the com- 

 paratively coarse silk of which they were composed would be small. 

 It is obvious that the volumes do not give a direct measure of the 

 density of the plankton, because the length of the column of water 

 through which the net fished varied from 20 to 120 fathoms, according 

 to the depth of water at the various stations. The volume of plankton 

 per cubic meter of water (coefficient of filtration neglected) was as 

 follows: — 



