FORM AND HABIT: THE WING. 



11 



organs we shall direct onr atteutioii to their external form 

 rather than their internal strnctnre. 



T/ie Wing. — Birds' wings are primarily organs of 

 locomotion, hut they are also nsed as weapons, as musical 

 instruments, in expressing emotion, and they are some- 



FiG. 4. — YouDg lioatzin, sliowing use of hooked finders in elimbiny 



Lucaa.) 



(•After 



times the seat of sexual adornment. As an organ of loco- 

 motion the wing's most primitve use is doubtless for 

 climliing. Gallinules, for instance, have a small spur on 

 the wrist or "hend ijf the whig," and the young lurds 

 use it to assist their progress among the reeils. A more 

 strilving instance of this nature is shown liy that shigular 

 South American bird, the H(jatziu {Ojjisthucoin.un cris- 

 3 



