202 



DR. a. H. FOWLER — BISCATAN PLANKTON 



The following table, for example, seems to show a concentration of the larvae below 

 the surface, but short of 100 fathoms, whether considered from their number of 

 occurrences * or from the average specimens per hour haul f . 







25 



50 



75 



100 



> 35 



2 " 



0-2 

 4-6 

 5-6 

 4-0 

 2-3 



1' , 



bX)- 



O Pj 



Further, a comparison of the hauls made in the dark hours with those made in 

 daylight seems to point to a slight upward movement of the larvae at night ; the 

 concentration of specimens rising from 75 fathoms to 25-50 fathoms. How far this 

 may be due to larvae rising from the mesoplankton below 100 fathoms it is impossible 

 to say, but it seems obvious that there was a great coacentration of fish-larvae at 25-50 

 fathoms during the dark hours. 



The following table exhibits the distribution of the captures by hauls and depths 

 (L= larvae). The first three hauls were made with the closing "mesoplankton 

 trawl." 



* Compare p. 190, above. 



t In these tables the actual numbers have been treated as in previous papers of the series, and hauls with the 

 net of 180 meshes per inch omitted. 



