PREFACE 



by a colleague, Mr. N. T. Nicoll, whose photograph o{ Explorer is given in 

 Plate II. 



All photographs are acknowledged in their legends, but it is a privilege 

 to record my gratitude to Dr. D. P. Wilson of Plymouth for so many 

 excellent pictures taken of the living creatures, both black and white and in 

 colour; to Mr. Peter David of the National Institute of Oceanography for 

 his beautiful colour photographs; to Dr. H. G. Stubbings of the Admiralty 

 for kind permission to use their Crown Copyright photographs in Plate 

 XXXIII w^hich are reproduced by permission from the Jotiriial oj the Royal 

 Naval Scientific Service. Also included are several excellent photographs by 

 Lennart Nilsson, reproduced by kind permission of the pubhshers, Messrs 

 Tidens of Stockholm from the book Life in the Sea (EngHsh edition by 

 G. T. Foulis & Co.) The lower picture in Plate XXXV is by D. F. S. 

 Raitt and in Plate XII by Margaret Nyblad. To the following publishers 

 I also acknowledge my thanks for permission to copy certain figures: 

 Cambridge University Press (13 and 14 from The Medusae of the British 

 Isles by F. S. Russell) ; The British Association for the Advancement of 

 Science (35); Messrs Frederick Warne and Co. Ltd (30 and 37 from The 

 Seas by Russell and Yonge). 



As a professional biologist working on plankton, I have had access to 

 materials and facilities that I would not otherwise have had, and chances to 

 meet fellow workers from all over the world. By courtesy of the Department 

 of Agriculture and Fisheries for Scotland, I have been able to use these 

 opportunities to the advantage of the reader. 



The verse on the title page is from the poem 'An oceanographer's dream' 

 (with apologies to Tennyson) by Walter Garstang, which is included in his 

 hook Larval Forms, Blackwell, Oxford, 195 1. 



The index includes references to scientific terms explained in the text 

 and subsequently used without further explanation. 



