The Eggs of Birds ace 
but sharp as is the eye of passing crow or beach-patrolling 
bear, the eggs to them would appear but bits of sand and 
shadow. 
And thus we might go on with many other examples 
of protection derived from the pigment on the shells— 
protection which in a hundred instances might prove: 
Fic. 360.—Eggs of Night-hawk. 
futile, but which in the great summing up and balancing 
of Nature’s profit and loss is of inestimable value to the 
race, 
We find an unusual condition in the colouring of the 
eges of sea-birds,—of certain of those species which nest 
on inaccessible cliffs. If pigment was developed in the 
