522 ZOOLOGY. 
While the sternum of the cassowaries and other struthious 
birds (Ratit@) is smooth, approaching that of reptiles, that 
of the higher living birds is keeled or carinate (Fig. 454, 
ers); hence these birds are called Cari- 
nate; to this keel and neighboring parts 
the muscles which raise and lower the wings 
are attached. 
The fore limbs of birds (Fig. 455) are 
greatly modified to form the framework of 
the wings. In spreading and closing the 
wings, the bones of the forearm slide along 
each other in a peculiar manner. (Coues.) 
The ulna is usually thicker and longer than 
the radius, and there are only two carpal 
bones, one radial, the other ulnar, in adult 
recent birds. The hand in the Apferyx and 
fh ae cassowaries has but one complete digit, 
seen from in front j while in other birds there are three digits, 
fone After Gegen- Which probably correspond to the first, 
is second, and third fingers of the human 
hand. The wings are attached to a strong shoulder-girdle, 
which consists of the two collar bones, uniting* to form the 
wish-bone, and of acoracoid bone and scapula. 
Fig. sean aha wing bones of a young Chicken, A, shoulder: B, elbow; C, wrist 
or carpus; D, tip of third finger; a, humerus; 6, ulna; c¢, radius; d, scapholunar 
bone ; ¢, cuneiform bone; f, g, epiphyses of metacarpal bones /. k, respectively ; h, 
metacarpal and its digit i—From Coues’s Key. 
The pelvis of birds is remarkable for the long slender back- 
wardly projecting ischium and pubic bones; there is generally 
* The clavicles are separate in the emeu and toothed birds; absent 
in the ostrich. 
