Index 



281 



Muskellunge, 220 



distinctive characters, 220 



Qgg hatching period 168 



growth, 221 



spawning, 221 

 Mutationist, 9, 10, il 



North Sea, 165 



Nostrils, 114 



Numbers of fish, in schools, 165 



Operations on fish, ears, 104 



fins, 59 



lateral line, no 



technics, 104 

 Optic nerves, 86-88 

 Optics, under water, 68-81 

 Organ systems, 16, 17 

 Ovaries, 1 71-172 

 Oxygen, In air-bladder, 133 



content of water, 147, 148 



requirements, 148 



source of, 148 



Pain, In fish, 11 9-1 2 1 

 Parasitic male, 269 

 Parent-stream theory, 189-199 

 Parr marks, 44 

 Perch, 48, 51 



illustrated, 50 

 Poikilo-thermal, 156 

 Poison, fish, 244 

 Pollution, 229 

 Ponds, farm, 246 

 Porcupine-fish, illustrated, 23 

 Porpoise, 14, 58 

 Predator, 38 

 Primitive fish, 48, 51 

 Protozoan, 14 



illustrated, 14 



PterichthySy illustrated, 8 

 Puffer, 223 



Ray {see also Cartilaginous fish), 

 251 



illustrated, 252 

 Reef-wrasse, 44 

 Refraction, 68-79 



critical angle, 71, 75 



in fish's optic mechanism, 83 



total, 71 

 Retractor lentis, 84 

 Remora, 258 



illustrated, 258 



Sacro-iliac, 55 

 Salmo solar y 184 

 Salmon, 184, 228 



artificial propagation, 165, 166 



Atlantic, 184 



by-products, 166 



caeca y 143 



Columbia River, 230-235 



eggs, 166 



homing instinct, 189, 1 90, 



I93> 195, 196 

 life history, 185 

 marking, 191-195 

 Pacific, 184 

 parr marks, 44 

 rate of travel, 188 

 Salmo salary 184 

 salmonidaey 174 

 spawning act, 189 

 spawning migrations, 187, 188, 



189 

 speciation, 11, 184 

 speed of, 58 

 survival, 189, 240 

 tagging, 192 



