PREFACE 



The study of life in the sea and the conditions there 

 prevailing has made very rapid advances within recent 

 years. Beyond "The Depths of the Ocean," by Sir John 

 Murray and Professor Johan Hjort, a book suited rather 

 to the needs of advanced students, there is no modem work 

 dealing in popular style with the science of oceanography 

 as a whole. It is true there are many books covering 

 particular aspects of the subject and especially that fringe 

 of the sea within the reach of all, the sea shore ; but the 

 latter deal solely with the local fauna that surrounds our 

 shores and tell nothing about that world that lies stretching 

 for miles in all directions beyond the coasts, the open sea 

 and oceans. It is in the hope of filling a gap in the litera- 

 ture of natural history that these pages have been written. 

 In preparing the book the authors have each written those 

 chapters dealing with subjects connected with their own 

 fields of research. It was thought that the ground would 

 be more fully covered in this manner than if all the chapters 

 were written in collaboration, and for this reason the 

 reader is asked to excuse any disparity in style that may 

 occur between the different chapters. Chapters I (first 

 half), IV, V, X, XI, XII, XIII, XV, and sections of XVI 

 have been written by Mr. Russell, and Chapters I (second 

 half). II, III, VI, VII, VIII, IX, XIV and sections of 

 XVI by Dr. Yonge. 



We should like to take this opportunity of expressing 

 our thanks to Dr. E. J. Allen, F.R.S., Director of the 

 Plymouth Laboratory, and to the members of the staff of 



