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PLANKTONIC FORAMINIFERA FROM THE 

 WESTERN NORTH ATLANTIC 



By RICHARD CIFELLI 



U. S. National Museuvt, Smithsonian Institution 



(With Nine Plates) 



INTRODUCTION 



The present paper describes and records the distribution of Fo- 

 raminifera collected in plankton tows from four seasonal traverses 

 between Cape Cod and Bermuda. Plankton stations were occupied 

 in the shelf waters, slope waters, Gulf Stream and Sargasso Sea (see 

 Appendix for details). The Gulf Stream stations, except for the fall 

 traverse, were determined by bathythermograph at the times of collec- 

 tion and were encountered at approximately longitude 69° W. In this 

 part of the North Atlantic the Gulf Stream is an important hydro- 

 graphic boundary, separating the temperate slope waters from the 

 subtropical Sargasso Sea. The chief purpose of this study was to 

 determine the influence of this boundary on the distribution of 

 planktonic Foraminifera. 



The four seasonal cruises were made in 1960 and 1961 aboard the 

 Woods Hole Oceanographic Institution vessels Chain and Crazvford; 

 the position of the stations are shown in figure 1. The summer and 

 winter stations are the ones that have been regularly occupied by the 

 Woods Hole Oceanographic Institution over a period of years in a 

 continuing program to study the biology and chemistry of the western 

 North Atlantic. The distribution of epizooplankton from those sta- 

 tions has been reported on by Grice and Hart (1962). 



The collections were obtained in oblique tows with a No. 10 

 plankton net having a |-meter open-mouth diameter. At shallow sta- 

 tions the net was lowered as close as possible to the bottom, and 

 beyond the shelf it was lowered to 2(X) meters. The ship's speed during 



SMITHSONIAN MISCELLANEOUS COLLECTIONS, VOL. 148, NO. 4 



