BIRDS. 301 



On each side of the well-known bone which is called the 

 " merry- thought " (furculum), is one of a less symmetrical 

 form, one extremity being thin and flat, while the other is 

 spread out into a stronger and broader shape. If these bones 

 be examined with reference to their uses in the framework 

 of the bird, we find that the thinner side of the last mentioned 

 is, in fact, one bone,* the broader side another bone,t consti- 

 tuting the great support of the shoulder; and that the 

 " merry-thought " is composed of two joined together, \ form- 

 ing a figure like that of the letter V, the whole being so 

 many buttresses to keep the shoulder joint firm and steady. 



It may not be uninteresting to contrast the skeleton of the 

 Ostrich (Fig. 237) with that of the Vulture (Fig. 240), and 



Fig. 240. SKELETON OF TUB VULTURE. 



to observe the difference they exhibit in the bones of the 

 wing, and several other particulars. 



The bones of birds are not, 'however, remarkable only for 

 their form or arrangement, but also for a peculiarity of 



* The Scapula. f The Coracoid. J The Clavicles. 



vc, cervical vertebrae ; vs, sacral vertebrae ; vq, caudal vertebrae ; st, sternum ; 

 cl t clavicles ; fi, humerus ; o, bones of the fore-arm ; c<i, carpus ; ph, phalanges ; 

 /, femur ; t, tibia ; ta, tarsus. 



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