IV 



PREFACE 



Captain W. J. Peters laid the broad foundation of the 

 work during the early cruises of both vessels, and Captain 

 J. P. Ault, who had had the good fortune to serve under 

 him, continued and developed what Captain Peters had 

 so well begun. The original plan of the work was en- 

 visioned by L. A. Bauer, the first Director of the Depart- 

 ment of Terrestrial Magnetism, Carnegie Institution of 

 Washington; the development of suitable methods and 

 apparatus was the result of the painstaking efforts of his 

 co-workers at Washington. Truly, as was stated by 

 Captain Ault in an address during the commemorative 

 exercises held on board the Carnegie in San Francisco, 



August 26, 1929, "The story of individual endeavor and 

 enterprise, of invention and accomplishment, cannot be 

 told." 



The following memoir by Dr. Arthur S. Campbell is 

 the second in the series of reports on studies of the 

 plankton gathered during the last cruise of the Carnegie. 

 Of value in this study of the oceanic Tintinnoina has 

 been the mass of material accumulated by other vessels, 

 especially the Albatross and the National, detailed ac- 

 counts of which are given elsewhere. 



J. A. Fleming 

 Director, Department of Terrestrial Magnetism 



