212 The Bird 



condor which was playfully galloping around the fright- 

 ened bird. 



Millions of years ago, in the geological period of time 

 known as the Jurassic, there existed gigantic sea-lizards, 

 which we call Ichthyosauri. All we know of them we 

 have learned by study of their fossil bones which, through 

 the ages, have been preserved in rocks. One notable 



FIG. 153. Brown Thrasher with eyes wide open. 



thing about them was the great size of their eyes meas- 

 uring as much as twelve and fourteen inches across. 

 These orbits were surrounded by a series of bony plates, 

 and in certain birds of to-day we find a similar circle of 

 small overlapping bones. 



To make the simile between a camera and an eye hold 

 good, we must show that the latter is provided with a 



