PREFACE 



genus Ceratium of the family Ceratiaceae. Dr. Graham 

 was assisted in the laboratory work necessary for the 

 present volume by Mrs. Natalia Bronikovsky, who did 

 the careful microscopic work which the dinoflagellate 

 investigations demand. 



The genus Ceratium is distributed over all the oceans 

 of the world and is one of the most valuable genera of the 

 peridinians for distributional studies. Not only are there 

 cold- and warm-water species, but many species show 

 minor phenotypic variations which are useful in tracing 

 dynamic conditions. Fifty-eight species of this genus 

 were found in the Carnegie material and are discussed 

 here. Distributional and environmental data for these 

 different species are given in the appendix tables (pp. 

 47-161) and charts (pp. 187-207) whenever such infor- 

 mation is available. 



The area traversed by the Carnegie was divided into 

 five regions on the basis of Ceratium floras (chart 45). 

 Two of these regions are in the North Atlantic and three 

 are in the Pacific Ocean. They are also characterized 

 by particular hydrographic conditions. 



This manuscript was completed by Dr. Graham in 

 1938. Thus some papers printed since then are not con- 

 sidered. 



The present volume is the eleventh in the series 

 "Scientific results of cruise Vn of the Carnegie during 

 1928-1929 under the command of Captain J. P. Ault." 

 This is the fifth of the Biological Reports. 



J. A. Fleming 

 Director, Department of Terrestrial Magnetism 



