146 
GENERAL ORNITHOLOGY. 
scapular arch, corresponding to the ratite and cariuate sternum. (1) In JRatitce the axes of the 
coracoid and scapula are nearly coincident (for the most part in a continuous right line) and 
anchylosed together; the clavicles are usually wanting, or defective; and the coracoids are in- 
stepped on the sternum far apart. (2) In all Carinatcs, the axes of the coracoid and scapula 
form an acute or scarcely obtuse angle (fig. 56, sglc); normally these bones are not anchylosed; 
perfect clavicles are present, anchylosed with each other, but free from the other bones ; and the 
coracoids are instepped close together. Decided exceptions to these conditions, as in Notornis, 
are anomalous ; though incompletion of the clavicles repeatedly occurs, as noted below. 
The Coracoid (Gr. /cdpa^, Jcorax, a crow ; ddos, eiclos, form : the corresponding bone of 
the human subject, which is the stunted coracoid process of the scapula," being likened to a 
crow's beak ; no applicability in the present case ; 
figs. 56, c, 59, c) is a stout, straight, cylindric bone, 
expanded at each end, extending forward, outward, 
and upward from the fore border of the sternum 
to the shoulder. Its foot is flattened and splayed 
to fit in the articular groove of fore border of 
the sternum already described; it often overlaps 
that of its fellow on the median line ; is narrower 
and remote from its fellow in JRatitce. The head 
of the bone, irregularly expanded, articulates or 
anchyloses with the end of the scapula, and also 
usually with the clavicle. It bears externally a 
smooth demi -facet, which represents the share it 
takes in forming the glenoid (Gr. yXrjvT], glene, a 
shallow pit; fig. 59, gl) cavity, which is the socket 
of the humerus. This articular expansion is the 
glenoid process of the coracoid : the clavicular 
process is that by which the bone unites with the 
clavicle. The relation between the heads of the 
three bones (each uniting with the other two) i& 
such that a pulley-hole is formed, through which 
plays the tendon of the pectoral muscle which ele- 
vates the wing. The coracoid is a very constant 
and characteristic bone of birds. 
The Scapula (Lat. scapula, the shoulder- 
blade ; figs. 56, 59, s) merits in birds its name of 
"blade-bone," being usually a long, thin, narrow, 
sabre-like bone, which rests upon the ribs — usu- 
ally not far from parallel with the spinal column, and near it ; but in BatitcB otherwise. 
It seldom gains much width, and is quite thin and flat in most of its length ; but it has a 
thickened head or handle, expanding outwards into a glenoid process which unites with that 
of the coracoid to complete the glenoid cavity, and dilated inward to form an acromial (Gr. 
cLKpco^iLov, acromion, point of the shoulder) process for articulation with the clavicle (as it does in 
man), when that bone exists. The other end is usually sharp-pointed, but may be obtuse, or 
even clubbed, as in a woodpecker. The scapula is broadest and most plate-like in the pen- 
guins, in which birds all the bones of the flipper-like wing are singularly flattened. In Ai^teryx 
it reaches in length over only a couple of ribs ; in most birds, over most of the thorax; and 
in some its point overreaches the pelvis. 
Fig. 59. — Right pectoral arcli of a bird, Pedice- 
cetes phasianellus, nat. size, outside view ; Dr. R. 
W. Shufeldt, U. S. A. s, scapula; c, coracoid; gl, 
glenoid, the cavity for head of humerus ; cl, clavicle ; 
he, hypocleidium. In situ, the right end of the fig- 
ure should tilt up a little ; see fig. 56. 
