MUSCULATURE. 271 
scapularis accessorius which is present likewise in the Proechidna. The origin 
is directly over the center of the glenoid cavity. It passes ental to the triceps 
back to the lesser tuberosity of the humerus where it inserts just distal to the 
insertion of the subscapularis. 
The teres major is a large flattened muscle arising from the extreme postero- 
dorsal angle of the scapula on the external side. It inserts on the humerus 
by a broad tendon slightly distal to the insertion of the subscapularis. 
The teres minor is lacking in both the Echidna and the Proechidna. The 
small muscle described as subscapularis accessorius can hardly represent this 
muscle, on account of its insertion into the lesser instead of the greater tuber- 
osity. According to Sabatier it is fused with the infraspinatus which seems 
extremely probable, since the latter is intimately connected along the anterior 
edge of the scapula, with the swpraspinatus where the latter passes out beneath 
the episternum. 
The coracobrachialis presents quite the same divisions as in the Echidna. 
The most superficial is the caput longum from the posterior tuberosity of the 
coracoid by a broad tendon. It passes as a broad muscular band to the internal 
distal condyle of the humerus where it is inserted by short tendinous fibers. 
Underneath this head, and from the same origin is the caput breve, which spreads 
out as a thin muscular sheet over the posterior aspect of the head of the humerus 
from the lesser tuberosity to the center of the depression between the two 
tuberosities, and distally for nearly three fourths the length of the humerus. 
The third portion is much smaller, and is wholly overlaid by the second head. 
It arises slightly anterior to the latter, in part from the lateral surface of the 
epicoracoid and passes as a short tenuous sheet to insert on the lesser tuberosity 
of the humerus just posterior to the insertion of subscapularis. This is the 
epwcoracobrachalis of Coues. 
The biceps arises from the ventral surface of the coracoid below the glenoid 
cavity. At its anterior edge may be separated off a small slip whose origin is 
from the epicoracoid. The two are closely approximated and after about 
20 mm. become inseparably fused to form a stout muscle that passes to a tendi- 
nous insertion nearly a centimeter in length on the medial side of the radius, 
nearly the same distance distal from the sigmoid cavity. The same condition, 
essentially, is found in the Echidna in which the small slip frony the epicoracoid 
is considered by Westling a second head. The action of the muscle is to ap- 
- proximate the fore arm to the breast. 
The triceps is very strongly developed, and is separable into the usual 
