PREFACE ix 



been taken for the purpose of ascertaining the number and distribution 

 of the organisms therein. So far the planktonts in about half of these 

 samples have been enumerated ; when the counting is completed, a bul- 

 letin dealing with this phase of the work in greater detail will be pre- 

 pared. 



The United States Bureau of Fisheries granted financial assistance 

 toward this investigation and grateful acknowledgment is extended for 

 this valuable aid. A more thorough study of the various problems 

 was made possible through this assistance. The results are published 

 with the permission of the Commissioner of Fisheries. 



