SECOND WEEK] February 47 



can distinguish details is apparent in the choice which a 

 trout exhibits in taking certain coloured artificial flies. 

 We may suppose from what we know of physics that when 

 we lean over and look down into a pool, the fishy eyes 

 which peer up at us discern only a dark, irregular mass. I 

 have seen a pickerel dodge as quickly at a sudden cloud- 

 shadow as at the motion of a man wielding a fish pole. 



We can be less certain about the hearing of fishes. 

 They have, however, very respectable inner ears, built on 

 much the same plan as in higher animals. Indeed many 

 fish, such as the grunts, make various sounds which are 

 plainly audible even to our ears high above the water, 

 and we cannot suppose that this is a useless accomplish- 

 ment. But the ears of fishes and the line of tiny tubes 

 which extends along the side may be more effective in 

 recording the tremors of the water transmitted by mov- 

 ing objects, than actual sound. 



Watch a lazy catfish winding its way along near the 

 bottom, with its barbels extended, and you will at once 

 realise that fishes can feel, this function being very useful 

 to those kinds which search for their food in the mud at 

 the bottom. 



Xot a breath of air stirs the surface of the woodland 

 pond, and the trees about the margin are reflected un- 

 broken in its surface. The lilies and their pads lie motion- 

 less, and in and out through the shadowy depths, around 

 the long stems, float a school of half a dozen little sunfish. 

 They move slowly, turning from side to side, all at once 

 as if impelled by one idea. Now and then one will dart 



