viii LIST OF ILLUSTRATIONS 



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PHOTOGRAPHING A DACE, LIGHTED BOTH FROM ABOVE AND FROM j 



IN FRONT 



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DACE 



DACE REFLECTING ITS DARK SURROUNDINGS . 

 PHOTOGRAPHING A DACE, LIGHTED ENTIRELY FROM ABOVE 

 DACE SWIMMING FREE IN THE POND ..... 

 SHOAL OF YOUNG RUDD SEEN AGAINST THE SURFACE OF THE 



WATER FROM THE BOTTOM OF THE POND .... 



ORANGE, BLACK, AND YELLOW PIGMENT CELLS IN SKIN OF LOACH 

 PIKE WITH TAIL IN THE LIGHT ...... 



PIKE WITH HEAD IN THE LIGHT . . . . 



TENCH, AS ACTUALLY COLOURED ...... 



TENCH, AS SEEN UNDER THREE FEET OF WATER IN THE POND . 

 TENCH, AS SEEN UNDER SIX INCHES OF WATER IN THE POND . 

 STONE LOACH, SHOWING ACTUAL ARRANGEMENT OF COLOUR AND 



MARKINGS ......... 



STONE LOACH, SHOWING HOW MARKINGS ALONE DO NOT CONCEAL 

 STONE LOACH, SHOWING HOW MARKINGS SEEN ON A UNIFORMLY 



COLOURED FISH DO CONCEAL . 

 PERCH AS WE SEE IT IN A TANK 

 PERCH AS IT APPEARS TO OTHER FISH IN NATURAL ENVIRONMENTS 

 LEMON SOLE SEEN AGAINST A WHITE BACKGROUND . 

 THE SAME FISH IN NATURAL SURROUNDINGS 

 SKIN FROM A STONE LOACH LIVING ON A MUDDY BOTTOM 

 SKIN FROM A STONE LOACH LIVING ON A SHINGLY BOTTOM 

 BABY PIKE SHOWING BARS .... 



PIKE WITH BARS CHANGING INTO SPOTS . 



DEAD PIKE, 21 LBS. IN WEIGHT, SHOWING SPOTS 



RUFFE, SHOWING THE FIN ON THE BACK AS A WEAPON OF DEFENCE 



COTTUS IN A WARNING ATTITUDE . 



BLENNY ASSUMING A WARNING ATTITUDE 



DOG-FISH ....... 



FEMALE DOG-FISH SWIMMING ROUND A ROCK . 



GROWTH OF THE EMBRYO RAY 



RAY ONE MONTH OLD ..... 



UNDER-SURFACE OF RAY, SHOWING MOUTH, NOSTRILS, AND GILL 



SLITS ......... 



YOUNG THORNBACK RAY LYING ON THE BOTTOM OF THE SEA 



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