LIST OF ILLUSTRATIONS 



Figure Page 



Frontispiece. --Securing the Clarke-Bumpus plankton sampler to the towing 

 cable aboard the Hugh M. Smith. 



1. Locations of stations 1-30 occupied by the Hugh M. Smith , cruise 16, July- 

 August 1952 2 



2. Reconstruction of the curvature of the towing wire during four test hauls 



utilizing wire-angle and wire-out observations . , 5 



3. Combined results of the four test hauls, plotted on a logarithmic scale, showing 

 the relationship between estimated depths based on straight-wire and curved- 

 wire calculations ° 



4. Vertical temperature section along 150 W. longitude, showing the estimated 

 hauling depths of the surface, intermediate, and deep samplers in relation 



to the temperature structure 7 



5. Bathythermographs representative of the vertical temperature structure in 

 the North Equatorial Current, the Countercurrent,and the South Equatorial 



Current, at the station positions indicated 7 



6. Logarithms of zooplankton volumes of Hugh M. Smith cruise 16 plotted against 

 the sine value corresponding to the hour of hauling, and showing the calculated 

 regression line for the relationship 13 



7. Variations in the horizontal and vertical distribution of zooplankton as measured 



on Hugh M. Smith cruise 16 15 



8. Horizontal and vertical distribution of eight major groups of the zooplankton 



sampled on Hugh M. Smith cruise 16 16 



9. Variations in average size of the organisms in the collections of cruise 16 

 calculated by dividing the displacement volume of the sample by the estimated 



number of constitutents 17 



