PREFACE 



The collections upon which this study has been based were made off the 

 coast of soi;thern California, in large part from June to August, 1906, and 

 from June to September, 1917. Preliminary observations on a number of the 

 more common and hardier species found in the inshore plankton have been 

 carj'ied on, mainly during the summer months, over a series of years by the 

 senior author; in 1901-1903 at the summer ]\Iarine Laboratory of the Uni- 

 versity of California at San Pedro and at Coronado Beach; in 1904-1907 at 

 the INIarine Laboratory of the San Diego Marine Biological Association and 

 in 1907-1917 at its successor, the Scripps Institution for Biological Research 

 at La Jolla, and at the Naj^les Biological Station in January-May, 1908, while 

 occupying the table of the Smithsonian Institution. 



Additional opportunities have been afforded to the senior author in the 

 Agassiz Expedition to the Eastern Tropical Pacific in 1904-1905, and in the 

 plankton traverse of the Northern and Western Pacific and Indian oceans 

 during a trip from San Francisco to Coloni])o, Ceylon and return in 191G, to 

 widen his knowledge of the dinoflagellates generally. The immediate results 

 of these observations are not, however, included in this paper. 



The junior author, who has been associated with the enterprise since July, 

 1915, spent the summer of the two sulisequent years at La Jolla, in work upon 

 these and other dinoflagellates. In June to September, 1917, the most intensive 

 work was done upon the naked dinoflagellates. The junior author spent three 

 months at La Jolla, with Miss Anna L. Hamilton as colorist, and was joined 

 by the senior author during the six weeks while the material was most abmidant. 



Much assistance Avas rendered in the earlier years by Mrs. Effie J. Rigden 

 Michener, and in the summer of 1914 by Miss Inez Smith, wdio made a careful 

 investigation of the dinoflagellate fauna of the beach sands. In the summer 

 of 1917 Miss Rofena Lewis, Miss Pirie Davidson, Miss R. E. Merrill and Miss 

 E. II. Logan gave material assistance in seeking for the elusive organisms and 

 in preliminary aualyis. 



The authors are especially indebted to ]\Iiss Anna L. Hamilton, to whose 

 artistic skill in the use of water colors and faithfidness in interpreting our 

 analytical sketches, our plates owe whatever technical merit they possess. We 

 are also indebted to ^liss Rofena Lewis for nnich valuable assistance in the 

 preparation of the ])il)liography and much of the clerical work connected with 

 the preparation of the material. 



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