94 The Lije Story of the Fish 



die of the band. If you take a few of these young ones, anes- 

 thetize them until they are absolutely motionless, and lay 

 them on the bottom of the tank, they are indistinguishable 

 to the human eye from the sand and debris collected there, 

 but not to the jewel. He picks them up and carries them 

 back to where they belong. Further, there is another species 

 of cichlid whose habits are the same, and whose young are 

 so much like the jewel in shape, size, and marking, that they 

 are difficult to tell apart without a microscope. If you take 

 ten of the jewel's children away from the flock, and a mo- 

 ment later return to a different part of the tank five baby 

 jewels and five of the other species, he will take them, one 

 by one, into his mouth to carry them back to where they 

 belong. Then, if you watch closely, you will see that each 

 jewel is spat out into the bosom of the family, but the little 

 strangers go into his mouth never to emerge. Instead of 

 joining the little jewels, they become part of a big jewel. 

 And what is more, even if both sets of young are rendered 

 motionless by anesthesia, to eliminate any telltale responses, 

 he can still tell them apart. That sight is the sense which 

 operates here, and not smell, has been demonstrated by ex- 

 periments which we do not need to go into. It is hard to 

 believe that there are any blurred lines in the picture on the 

 jewel's retina. 



Let us now consider the trout. The trout unquestionably 

 sees the fly before It hits the water. One method of attracting 

 his attention, in dry-fly fishing, is to make false casts just 

 over him, without allowing the fly to come down. He has 

 been known to leap out of the water after the fly, and, 

 although it is always dangerous to apply what is known of 

 one species to another, this indicates that he has at least 

 some of the abilities of Toxotes when it comes to seeing 

 things above the surface. As for flies on the surface, we all 

 know that he has not only extremely keen perception in 



