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Show 1892.] MUSCULAR ANATOMY OF AULACODUS. 521 of the sterno-scapular; these may possibly be regarded as being collectively the equivalent of the pectoralis minor of other animals. Both Sterno-mastoid and Cleido-mastoid are present; the latter is of about half the size of the former and arises from the middle of the clavicle. The Omohyoid is present and is large. The Levator claviculee is continuous with part of the panniculus carnosus. The Latissimus dorsi is a large muscle and gives off a good-sized dorso-epitrochlear slip to the elbow; the latter is 8 m m . across ; the latissimus dorsi is inserted in common with the teres. The Trapezius is extensive; it is continuous with part of the panniculus, but its strong tendon can be seen to be separate. The Rhomboideus is attached along the whole length of the vertebral border of the scapula and also ventrally to the fascia covering the supra-spinatus and to the spine of the scapula itself, just at the point where the spine ends in the vertebral border of the scapula. The Sterno-scapular is in two parts: the shorter and narrower part arises from the sternum and from the cartilage of the first rib; it is about 5 m m . across near to its origin ; at the insertion it splits into two parts-one entirely muscular, the other nearly entirely tendinous; the former joins the fourth part of the pectoralis, the latter becomes continuous with the second and larger half of the sterno-scapular. The Deltoid is a double muscle: one part arises from the clavicle, the other from the metacromion; they are inserted together above and to the outside of the insertion of the pectoralis to the deltoid ridge. The Biceps is double-headed; the short head arises in common with the coraco-brachialis. The Coraco-brachialis is a single muscle; its insertion extends 7 m m . beyond the insertion of the teres. The Brachialis anticus has two heads of origin. The Triceps is, as usual, a very massive muscle ; the scapular head is the largest^ and arises also partly from the fascia covering the infraspinatus. The Teres major ends in a flat tendon, 9 m m . across, which is, as has already been mentioned, inserted in common with the latissimus dorsi. The Subscapularis commences about 12 m m . away from the vertebral border of the scapula. The Pronator radii teres is inserted on to the middle of the shaft of the radius; the half nearest to the insertion has a glistening tendinous surface. The Flexor carpi radialis arises from the flexor condyle of the humerus; its tendon begins 30 m m . from the origin. The Flexor carpi ulnaris is a large muscle; the tendon, which is broad and strap-shaped, is the widest of all the flexor tendons. The Flexor sublimis arises from the flexor condyle and from the septum between itself and the flexor profundus; it receives an excessively |
