224 The Bird 
More than a single volume could be filled with in- 
teresting facts about the bills of birds and the uses to 
which they are put,—hardly any two species using their 
beaks in a similar manner. The general way in which 
the vast subject of the adaptation of the bird to its needs 
and to its surroundings is treated in this volume will, 
it is hoped, be a stimulus to the reader to observe for 
himself,—to discover the thousand and one facts to 
Fic. 162.—Beak of Snapping-turtle. (Courtesy of N. Y. Zoological Society.) 
which Nature has not yet given us the key. Our lan- 
guage is too often lacking in phrases expressing delicate 
shades of meaning, and thus we are compelled to identify 
structures among the creatures which rank below us 
with portions of our own anatomy corresponding only in 
relative position or a general vague likeness of function. 
We are accustomed to speak of the mouth of a starfish, 
the arms of a sea-anemone, the foot of a snail: in these 
respective cases, structures specialized for receiving food, 
