OSTRICH . — Struthio camelus. 
CURSORED OR RUNNING BIRDS. 
ITH the Ostrich commences a most important group of 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 belonging to this order have the legs developed to an extra- 
ordinary degree, the bones being long, stout, and nearly as solid as those of a 
horse, and almost devoid of the air-cells which give such lightness to the 
bones of most birds. By the aid of the microscope, the peculiar character of the 
bone is clearly shown, though the bone 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. The huge wing muscles which give such prominence to the 
breast of flying birds, are therefore not required, and the breast-bone is consequently devoid of 
the projecting keel, and is quite smooth and rounded. 
