282 



Index 



Salnionidaey 174 



classification, 175, 176 



origin, 175 

 San Joaquin River, 235 

 Sardine, 226 

 Sargasso Sea, 262 

 Scales, 22 



annual check, 27 



of aquarium fish, 30 



growth of, 25-27 



nuclei, 25 



number of, 26 



position of, 25 



regenerated, 29 



rings, 26 



spawning mark, 27 



of tropical fish, 30 

 Scale-reading, 26-28 

 Scale-taking, 21 

 Schools, size of, 165 

 Schmidt, Johannes, 261 

 Screens, fish, 235 



electrical, 235 

 Sea-cucumber, 256 

 Sea-horse, 61, 249 



illustrated, 249 



spawning, 267, 268 

 Seasons, spawning, 168 

 Semi-permeable membranes, 150 

 Sense organs, 66 

 Sex-reversal, 267-268 

 Sexual selection, 44 

 Sharks {see also Cartilaginous 



fish), 46 

 "Shark-sucker," 258 

 Shasta Reservoir, 236 

 Sight, 67 



color discrimination, 96 

 distance judgment, 90-96 

 effect of current, 79 



Sight (Cont.) 



effect of reflected light, 78 



effect of waves, 79 



limits of vision, 71 



opacity of surface, 71 



optics under water, 68-81 



reflection, 71 



refraction, 68 



refraction, total, 71 



vision, acuteness of, 97 



vision, at close range, 93, 94 

 Skeleton, 47, 53 

 Skin, 17, 22 



living cells of, 17 

 Sleep, 100 

 Slime, 19-21 

 Slippery Dick, lOO 

 Smell, 113, 114 

 Smelt, Great Lakes, 224 

 Sounds, produced by fish, 106, 



135 



Spawning, 159 



of betta, 160, 161 



of black bass, 167, 217, 218 



intervals, 168 



of jewel, 161, 162 



of live-bearers, 163 



of mackerel, 159 



of muskellunge, 221 



migrations, 187, 191-195, 259, 

 264, 267 



of salmon, 187, 188, 189 



seasons, 168 



of shark, 164 



of tarpon, 201, 202 



of trout, 159, 160, 166, 167, 

 179-183 

 Specific gravity of fish, 53 

 Speed, of fishes, 58 



of other animals, 58 



