COLUMBA. 373 
compound bone so produced is called the furcula; the 
coracoid is very large and powerful and the scapula is long 
and flat. The coracoid and scapula form the glenotd cavity 
between them, and on the inner side the three bones border 
the foramen triosseum. The coracoids rest upon the front 
end of the enormous szernwm, their ends being fastened in 
its coracoid grooves. Projecting ventrally is the large keel 
or carina and laterally there is a costal process, followed by 
an indented costal ridge, to which the distal ends of the ribs 
are attached. 
The fore-limb has a short and powerful Aumerus, a thick 
ulna and a rather more slight vadzus, followed by a pair of 
proximal carpal bones. These are succeeded by a single 
Fig. 266.—THE SKELETON OF a BirD’s WING. (4d nat.) 
Carpo-metacarpus. _— Carpal. Radius. Humerus. 
First 
Third Metacarpal. 
Third Digit. 
ist Phalanx 
of 
Second Digit. 
end 
Phalanx. 
compound bone, the development of which shows it to be 
composed of the distal carpals and three metacarpals fused 
together. It is hence termed the carpo-metacarpus. It 
bears a first digit with a single phalanx, a second .digit 
with two large phalanges and a third with one small one. 
Hence the two peculiarities of the bird’s forearm are the 
fusion of distal carpals and metacarpals into one bone and 
the loss of the two last digits. 
To the first digit is attached the a/a spuria, a miniature 
wing. To the hind-border of the second and third digits and 
the carpo-metacarpus are attached the twelve primary quill- 
feathers, and to the ulna are attached the twelve secondary 
quill-feathers. 
