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Show 1890.] HELODERMA SUSPECTUM. 167 is here divided into two parts: the most posterior part envelops the hinder border of the scapula and suprascapula in a fleshy mass, encroaching slightly upon the adjacent surface of the coracoid. After this it converges to form rather a strong tendon, which is subsequently joined by the weaker tendon from the second part. This latter arises from the inner surface of the corresponding coracoid, covering a longitudinally-placed, elliptical area, occupying the greater share of its lower third. As already intimated, its tendon joins the tendon of the first part, just beyond the border of the coracoid, when almost immediately they become inserted into the distal margin of the head of the humerus at its posterior aspect. Between these two divisions of the subscapularis, the sternocosto-scapularis muscle is inserted, upon the mesial aspect of the shoulder-blade. Externally, the subscapularis covers by its origin about half of the scapula, extending but very slightly upon the suprascapula, and in this locality is covered for its anterior portion by the infraspinatus. Just before inserting its tendon upon the humerus, a portion of the former is deflected and so expanded as to become inserted into the juxtaposed capsular ligament of the shoulder-joint, and this part of the insertion of the subscapularis seems to be enjoyed by tbe muscle among most Lizards. Fiirbringer and Hoffmann term this muscle the subcoracoscapularis, but the name I here adopt for it is the one that has been used by Mivart, Sanders, Stannius, Pfeiffer, Rudinger, and other anatomists. 31. The Biceps here arises but by a single tendon, of some considerable width, which has its origin upon the external surface of the coracoid of the same side, it being limited to a curved line on the posterior moiety of the bone immediately within the line of the sterno-coracoidal articulation. The muscle passes directly down to a point just in front of the elbow-joint. It is not until it gets opposite the head of the humerus, however, that the thin flat tendon of the biceps becomes carneous, and even here it does not show any disposition, as it does nowhere else throughout its extent, to divide so as to exhibit anything that might be compared to two heads. At the middle of the brachiurn the muscle is considerably bellied and fleshy. Opposite the elbow-joint it again becomes tendinous, and its tendon here is transversely disposed, binds down the anterior aspect of the brachialis anticus muscle, as it spans the interosseous space, and finally is inserted into both the ulna and the radius, the ulnar insertion being much the stronger of the two. Sauders found that the biceps is only represented by its coracoidal head in Liolepis, while Mivart found that in Parson's Chamseleon its insertional slips arched over the brachialis anticus muscle, exposing the latter to view in front, and he says of it, that "Descending in front of the insertion of the pectoralis, it there becomes fleshy, and becomes more or less divisible into two bellies, which embrace the brachialis anticus in front, but leave part of the latter visible within and without the arm." As I have just said, here in Heloderma it covers the brachialis anticus, and simply spans the interosseous space in front of it as it makes its double insertion, |