EMERSON: ANATOMY OF TYPHLOMOLGE. 
65 
inserts on the anterior border of the scapula, dorsal to the omo- 
hyoideus. 
«/ 
The latissimus dorsi is similar to the trapezius in shape and ori¬ 
gin, but it arises posterior to the scapula. It inserts on the dorsal 
part of the posterior border of the scapula. It serves, with the 
serratus magnus, to draw the scapula upward and backward. 
The serratus magnus (thoracico-scapularis), a short thick muscle, 
arises by two heads, one from the inner surface of the scapula near 
the postero-dorsal angle and the other anterior to this. Both parts 
unite and probably insert on the third or fourth rib, though I was 
unable to determine this with certainty. 
Intrinsic muscles. — On the outer surface of the scapula lies the 
suprascapular is, arising from the dorsal portion of the outer sur¬ 
face, with the exception of the anterior and the dorsal border, and 
inserting on the dorsal part of the head of the humerus. 
On the inner surface of the scapula, arising from the antero-ven- 
tral part of it and the posterior part of the procoracoid, is a slender 
Y-shaped muscle, sub scapular is, inserting on the inner dorsal part 
of the proximal end of the humerus, between anconeus coracoideus 
and anconeus scapularis medius. 
Ventral Surface. 
The muscles of the ventral surface are also divided into two 
groups, extrinsic and intrinsic. 
Extrinsic muscles. — The pectoralis, by far the largest muscle of 
the fore limb, is a superficial sheet partially covering the supracora- 
coideus and the rectus abdominis. Its anterior portion arises with 
the corresponding part of its fellow from the mid-ventral line, its 
posterior portion from the rectus abdominis and the aponeurosis of 
the external oblique. Its libers converge to its insertion on the dis¬ 
tal part of the lateral process of the humerus. It acts as an adductor 
of the fore limb. 
Intrinsic muscles. — The coraco-brachialis longus, a slender 
spindle-shaped muscle, arises from the posterior border of the pro¬ 
coracoid near the anterior rim of the glenoid fossa and inserts on the 
distal two thirds of the inner surface of the humerus. 
The coraco-brachialis brevis is much shorter and very slender. 
It arises from the postero-ventral border of the coracoid, and is cov- 
