62 THE SEA-SHORE 



Think of it in this way. 



Suppose that you take a telescope and look 

 through it. You can only see the objects at 

 which the telescope is pointed, not the objects 

 above it, or below it, or on each side. But if 

 you had four thousand telescopes, fastened to- 

 gether in two bundles of a couple of thousand 

 telescopes each, all pointing in different direc- 

 tions, and if your eyes were made in such a way 

 that you could look through all the telescopes at 

 once: then you would be able to see all round 

 you, though you would only be able to look in 

 any special direction through just one or two 

 of the telescopes. 



Now that is very much like the way in which 

 the eyes of crabs are made. Each of these four 

 thousand eyes is really a kind of telescope. And 

 as they all point in different directions, the crab 

 is able to see above it and below it and on all 

 sides, though it only looks at any special object 

 through one or two eyes. 



HOW CRABS HEAR AND SMELL 



The way in which crabs hear and smell is 

 almost as curious as the way in which they see, 

 for they have very odd little ears and noses in 

 very odd places. 



