The Eggs of Birds Ag1 
—one end blunt and narrowing to the other—that they 
have given to it its name: oval. In the eggs of certain 
sea-birds which breed on the narrow ledges of perpendicular 
cliffs this oval shape is carried to an extreme, and ap- 
parently for an excellent reason, mechanical, but of ines- 
timable value to the birds. Eggs laid in such positions 
Fie. 343.—Egg of Murre. 
are of course especially exposed to danger from the wind 
or from some sudden movement of the birds, which gener- 
ally nest very close together. Were it not that the eggs, 
on account of their peculiar shape, describe an arc of 
very small diameter when they roll, doubtless a far greater 
number would roll off and be dashed down upon the 
rocks below. Among the plovers, sandpipers, and phal- 
aropes we again find a peculiarly pronounced pyriform 
