STRUCTURE OF THE OSTRICH. 591 



conformation of birds, and in many of its pecu- 

 liarities of structure it makes some approach 

 to that which characterises the quadruped. 

 Though this bird is provided with wings, it was 

 evidently never intended that they should be 

 used for the purposes of flight. Hence the 

 chief muscular power has been bestowed on the 

 legs, which are remarkably thick and strong, 

 and well fitted for rapid progression. The ster- 

 num is flat and does not present the keel-like 

 projection which is so remarkable in that of 

 all other birds. The clavicles do not reach the 

 sternum, nor even meet at the anterior part of 

 the chest to form the furcular bone : for as the 

 wings are not employed in flying, the usual 

 office of that bone is not wanted. The form of 

 the pelvis is different from the ordinary struc- 

 ture ; for the pubic bones, which in all other 

 birds are separated by an interval, here unite as 

 they do in quadrupeds. 



The feathers are unprovided with that elabo- 

 rate apparatus of crotchets and fibres, which are 

 universally met with in birds that fly. The 

 filaments of the ostrich's feathers, in consequence 

 of having none of these fibrils, hang loose and 

 detached from one another, forming the fine hair 

 or down, which, however ornamental as an 

 article of dress, must be viewed, when con- 

 sidered physiologically, as a species of degene- 

 racy in the structure of feathers. 



