■'m-a-A, 



O&TSiCa.—airul/uu camelus. 



CURSORES, OR RUNNING BIRDS. 



ITTI the Ostrich commences a most imixjrtant gronp ol" birds, containing the 

 largest and most powerful members of the feathered tribe, and termed Cursores, 

 or Running-Birds, on account of their great speed of foot and total impotence of 

 wing. All the birds l)elonging to this order have the legs developed to an extra- 

 oi'diuary degree, the l)ones being long, stout, and nearly as solid as those of a 

 horse, and almost de\'()id of the air-cells \\hich give such lightness to the 

 bones of most birds. By the aid of the mi(^roscope, the peculiar character of the 

 bone is clearly shown, though the 1)one of an Ostrich or Cassowary is very different from the 

 same bone in a fowl or a pigeon. The wings are almost wanting externally, their bones, 

 although retaining the same number and form as in ordinary birds, being very small, as if sud- 

 denly checked in their growth. Tlie huge mng muscles which give such prominence to the 

 breast of flying birds, are therefore not reqnired, and the breast-bone is consequently devoid of 

 the projecting keel, and is quite smooth and rounded. 



