INTRODUCTION xiii 



light is from in front instead of from above, as in 

 the pond. 



Some of the photographs of fish in their natural 

 environments — for example, the young thornback ray 

 facing page 44 — are taken with the camera above the 

 water. When taking a photograph of this kind, it is 

 necessary to cut off the rays of light from the surface 

 of the water, either by means of a shield held at a 

 suitable angle, or by means of a tube in which is 

 fixed the camera, the end of the tube being under 

 the surface of the water. 



The micro -photographs of fish life are taken with a 

 special apparatus constructed for the purpose. All the 

 illustrations, except those of colour cells, scales and 

 teeth, are from living fish, and the photographs showing 

 methods of concealment are from straight prints and 

 untouched negatives. 



It is possible some may read this book who have 

 never previously taken any interest in fish. For their 

 information I show a rainbow trout, with the chief 

 external features numbered and marked. 



I take this opportunity of thanking Professor Herd- 

 man for having enabled me to obtain photographs 

 of the developing plaice, and Mr. Richmond, of the 

 Surrey Trout Farm, Shottermill, for numerous fish and 

 eggs supplied, and for interesting information with 

 regard to the salmon family. 



Among others who have assisted me in gathering 

 material for this book, I would especially thank Dr. 



