1920] Alien: Plankton of the San Joaquin River 



ACKNOWLEDGMENTS 



This investigation owes its origin to the committee in charge of 

 the survey of San Francisco 13ay, of which Professor Charles A. 

 Kofoid, is chairman, and was undertaken under the auspices of the 

 United States Bureau of Fisheries, to which I am indebted for equip- 

 ment of nets and supplies. 



Both Dr. F. B. Sumner and Waldo K. Schmitt, successive natural- 

 ists of the United States Steamship "Albatross," have lent their en- 

 couragement to my efforts and have also titrated some water samples. 

 For literature, or assistance in securing it, sincerest thanks are hereby 

 given to Professor S. A. Forbes, of the Illinois State Laboratory of 

 Natural History, to the Michigan State Fish Commission, to Professor 

 H. W. Conn of Connecticut, to Professor H. B. Ward of the Univer- 

 sity of Illinois, to Dr. A^incente Izquierdo of Santiago, Chile, to the 

 United States Geological Survey, to the Chief of Engineers of the 

 United States War Department, to Professor F. E. Clements of the 

 University of Minnesota, to Dr. William F. Allen of the University 

 of Minnesota, and to the Library of the University of Minnesota, to 

 Dr. C. Dwight Marsh of the United States Bureaii of Plant Industry, 

 to Mr. H. K. Harring of the LIuited States Bureau of Standards, to 

 Professor C. J. Elmore, Grand Island, Nebraska, to Dr. B. W. Ever- 

 mann of the California Academy of Science, to Professor E. A. Birge 

 of the University of Wisconsin, and to Professor C. A. Kofoid of the 

 University of California. 



Dr. IMarsh and Mr. Harring have also very kindly made some 

 identifications of eopepods and rotifers. Very material aid has been 

 given by Mr. E. P. Higby of the California State Hospital at Stock- 

 ton, who has given full use of his weather records, and to Mr. Law- 

 rence Backes of Stockton for photographic views of the stations. 

 Above all it should be said that whatever value there may be in the 

 present paper is largely dependent upon the advice, encouragement 

 and assistance of Professor C. A. Kofoid; and upon the painstaking 

 care with which Mrs. W. E. Allen has computed, recorded and pre- 

 served most of the data as they came to hand. Inasmuch as Professor 

 Kofoid 's report on the Illinois River has been in constant use for ref- 

 erence and guidance it has been used liberally for suggestive outline 

 of discussion. Many of its generalizations and conclusions are assumed 



