CORACOID BONES. In the mammalian skeleton, the scapula or blade-bone presents a bony process termed the corticoid process, from its supposed resemblance to a crow's beak (Lat. kTrar, a crow); and from the idea that the bones which we are now describing, and which exist in all birds, in saurian and chelonian reptiles, and in the tuonotremata, correspond anatomically with the comparatively slightly developed eoracoid process, they have received the name which is now universally assigned to them.
As the uses of these bones are most obvious in birds, we shall confine our remarks to this class of animals. It is obviously necessary that the scapular arch should be very strong in birds, in order to form a solid resisting fulcrum to the powerful movements of the humerus and other wing-bones. The scapula is a long, curved, compressed bone, extending along time back on each side of the dorsal vertebrae, imbedded in the muscles to which it gives attachment, while at its fixed extremity it assists in forming the cavity of the shoulder-joint. The corticoid bone is the great support of the shoulder; for while
at one extremity it. sustains the wing, at the other it is firmly secured to the sternum by a broad and strong articulation; indeed, it forms the main- resistance to the approx imation of the humerus to the median plane, and retains it firmly in its lateral position. The scapula and coracoid bone are anchylosed (or united by osseous matter) at their point of union, thus forming collectively the structure popularly known as the side-bone. The clavicles, which are conjoined to form the furcula, combine to add to the stability of the whole apparatus.