10 THE SEA-SHORE 



In the first place, their colour changes. Until 

 now, both sides of the body have been pearly or 

 silvery white. A white fish, however, lying on 

 yellow sand or brown mud, would be very easily 

 seen, and some hungry creature would be sure to 

 catch sight of it and devour it. So as soon as the 

 little fish lies down the upper side begins to get 

 darker, and in a very short time it is of just the 

 same colour as the sand or mud all round it. If 

 you look into a shallow pool in which some of 

 these fishes are lying you will find it very difficult 

 indeed to see them, for they look exactly like the 

 surface on which they rest. 



In the second place, their way of swimming 

 changes. When they first hatch out from the egg 

 these little fishes swim just as other fishes do- 

 upright, by means of their tails. For of course 

 you know that fishes do not swim with their fins, 

 which merely help them to keep their balance in 

 the water. But when they lie down at the bottom 

 of the sea they give up this way of swimming, and 

 wriggle their way, as it were, through the water, 

 still lying upon one side. 



But the oddest change of all takes place in 

 the position of the eyes. You can easily see, of 

 course, that if a fish with its eyes in the usual 

 place lies down on one side at the bottom of the 

 sea, one eye is underneath its head, and is quite 

 useless. So you might think that, except when 

 it was swimming, it would only be able to see 



