SKELETON OF BIRDS. 507. 
Bi the muscles that raise the wings, is very narrow in 
ee a 
a 
in accordance with their small demand for muscular 
er in this direction. This narrow scapula forms one part 
of what is known as the “side-bone ;” the other part ¢ of 
which is formed by a bone termed the coracoid, that is only 
epresented in Man and other Mammals by the short coracoid 
process of the scapula 
(§ 635). The two clavi- ed 
igs sescageapeaig ' 
e join the ster- 
a0 to rm the fork- 
like bone known as the 
merry - thought,” the 
strength of which, like 
the projection of the keel 
of the sternum, serves 
to indicate the power of 
flight, by the degree of 
eae winch it is. ca- Fig. 250.—Boxes or THE SHOULDER AND 
pable of affording to the “* ”“"Basasr or Braps. 
7 awing-together of the 0, scapula; ¢, coracoid bone; f, clavicles united 
houlder-joints by the ‘at their junction with the summit of the Keel 
don of the pectoral 00 semen sya ome 
muscles. The bones of 
he pinion consist of the humerus (fig. 249, hk), the two ‘eae 
the fore-arm o, the bones of the wrist ca (which are here 
Bearcely developed), and the bones of the fingers ph, each 
joint of which shows indications of being made up of two or 
Hhree separate bones united together. In no bird are these 
aquired for any other purpose than that of supporting the 
ing-feathers.—The leg is connected with the spinal column 
y a pelvis, of which the iliac bones are greatly lengthened 
firmly attached to the spine, but which is not completed 
9 a ring by the junction of the bones in front, as in Mam- 
fals ; such a completion would have prevented the 
the bulky eggs deposited by these animals (§ 755). In the 
nder extremity we find the femur or thigh-bone (principally 
meealed in the figure by the bones of the wing), the two 
bones of the leg ¢, which are commonly united in part of their 
h, the shank or ancle-bones ta, which are peculiarly: 
