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Show 168 DR. R. W. SHUFELDT ON [Apr. 1, and it agrees with all these forms in possessing only its coracoidal head. 32. Coraco-brachialis brevis.-This is one of the deep muscles of the shoulder-girdle found upon the anterior aspect of the chest, and is here very well developed. It arises from the outer surface of the coracoid, between the rounded, posterior angle of that bone to a point anteriorly next to the origin of the teres minor. Its area of origin is luniform, the concavity being towards the humerus ; and agreeing in form, posteriorly, with the coracoid, which in this locality it nearly covers. Its fibres converge as they pass towards the humerus, upon which bone the muscle is inserted, the insertion being upon a line extending from the head of the bone to a point at the junction of upper and middle thirds, on its anterior surface : the coraco-brachialis brevis also makes a partial insertion into the capsule of the shoulder-joint. Posteriorly, this muscle is firmly overlapped by the thin, flat tendon of the biceps, while more anteriorly some of the superficial muscles cross it to the humerus. 33. Coraco-brachialis longus.-This is a very differently characterized muscle from the one I have just described, it being long and slender, passing parallel to the humerus for its entire length. It arises, upon either side, from the posterior rounded angle of the coracoid, making slight encroachment upon the adjacent posterior surface of the bone. From this origin this long and fleshy muscle goes directly to the internal condyle of the humerus, into which it inserts itself: its insertion also extends slightly up the shaft of the bone, while its fascia merges with the fascia of the shoulder-joint. Sanders, Fiirbringer, and Hoffmann all adopt the same names for these muscles as I have given them here, the first-named authority using them in the case of Liolepis belli as early as 18/2. Both the coraco-brachialis brevis and longus are invariably present, so far as I am aware, in all true Lizards. 34. Brachialis anticus.-Comparatively larger than we find it in many Vertebrates, this muscle becomes one of the important ones of the arm, being even larger than the biceps. It arises, somewhat tendinous, from the entire antero-external aspect of the shaft of the humerus, from tuberosity to condylar extremity, being intimately associated with the triceps upon its inner side, and in contact with the biceps externally. Passing between the muscles of the forearm in company with the tendon of the biceps, it inserts itself, tendinous, into the proximal extremities of the radius and ulna, upon their anterior surfaces, being largely covered by the insertional tendon of the biceps in front. Fiirbringer terms this muscle the " humero-antebrachialis inferior," a name also adopted by Hoffmann ; it being the brachialis anticus of Mivart and the brachialis internus of Riidinger. It generally inserts itself into both bones of the forearm, but Mivart found that in Chamceleon parsonii this muscle inserted itself only into the ulna. 35. Triceps.-This thick and powerful muscle at the back of the arm, here in our present subject exhibits four points of origin, viz.:- |