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 Jchthyosauri. 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 
Fic. 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 
