PLANKTON OF THE GULF OF MAINE 



329 



That Eukrohnia should so seldom have been captured in the many tows that 

 have been made between the surface and 60 meters in different years and seasons 

 and in various parts of the gulf is sufficient evidence that it is only an accidental 

 visitor to the upper strata of water there; so much so, indeed, that we have learned 

 not to expect it shoaler than 75 meters except on rare occasions. 



0/ 



<u 



Fig. 91.— Numbers of specimens of Eukrohnia hamala taken in hauls from different depths at selected stations. In the 

 case of closing-net hauls the depth zone is bracketed 



Its scarcity at 60 to 100 meters, contrasted with its comparative abundance in 

 deeper water, illustrated by the accompanying diagram of the catches of Eukrohnia 

 at representative stations where two deep horizontal tows were made at different 

 levels (fig. 91) points to the 100-meter level or thereabouts as about the upper limit 

 to its common and regular occurrence. Below 100 meters, however, it has been de- 



