MYOLOGY OF OPISTHOCOMUS CRISTATUS. 307 
to the costo-coracoid membrane against which it is immediately applied. It is expanded 
and rounded at its distal extremity, corresponding to the club-shaped lateral extremity 
of the sternum between the incurvated great pectoral origin. Its tendon of insertion 
commences on the coracoid, and plays over it in a pulley-like fashion, crosses the head 
of the humerus to a prominent ridge on the middle of the dorsal surface, immediately 
above the articular facet on the summit of the great tuberosity of the humerus. 
The 3rd pectoral has its usual origin. It is moderately well developed. It runs 
almost parallel with the coracoid, crosses behind the coraco-brachialis; its tendon of 
insertion glides over the pulley-like summit of the ulnar tuberosity of the humerus to 
be inserted into a depression immediately below the tuberosity, and below the insertion 
of the teres major, the latter muscle crossing it obliquely. This muscle and the 
coraco-brachialis cover the axillary space, and are applied directly against the axillary 
vessels and nerves. 
The coraco-brachialis is inserted into the summit of the inner tuberosity of the 
humerus by a short slender tendon, which joins with that of the subscapularis. 
The subscapularis arises from the anterior two-thirds of the ventral surface of the 
scapula ; it is a triangular-shaped muscle, and rapidly converges towards its insertional 
tendon. It is crossed by the coraco-brachialis and the 3rd pectoral. The tendon of 
the latter muscle lies imbedded in the muscular fibres of the subscapularis, but does not 
divide it into two parts, as described by Owen in other birds. 
Depressor coracoideus and costo-scapularis are closely associated at their origin, arising 
as a broad, but thin, muscular band from the anterior external angle of sternum, and 
Ist sternal rib as far as its angle. The muscle then divides into two portions—the 
coracoid factor passing obliquely upwards, forwards, and outwards, to be inserted into 
the sternal 3rd of the coracoid, its lower border and posterior surface; the scapular 
factor is slender and elongated, and passes horizontally outwards, terminating in a short 
flattened tendon, which is inserted into the ventral border of the scapula about half an 
inch posterior to its articular extremity. The subscapularis muscle lies in front and 
partially conceals it. It is applied for half its length against the 1st vertebral rib. 
Teres major, large, fleshy, and wedge-shaped, arises from the anterior border of the 
lower half of the scapula, and from the posterior two thirds of its dorsal aspect. It 
terminates by blunted cone-shaped musculo-tendinous fibres in a large depression situated 
below the inner tuberosity of humerus. There was no scapular attachment as mentioned 
by Owen in the birds which he dissected. 
Serratus magnus isa thin muscular band imperfectly developed. It arises, apparently, 
from the 3rd, 4th, and 5th vertebral ribs, about midway between the sternum and the 
vertebre. It is inserted into the lower third (or a little more) of the ventral border of 
scapula, and also into the inferior angle. 
The supraspinatus is represented by a small muscular fasciculus. 
I did not notice in either of the two specimens the small muscular slip, called by Owen 
