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Show 846 . MR. F. E. BEDDARD ON THE [Dec. 3, portion extending as far back as the margin of the thigh; this has been already described by Maurer1 and its resemblances to a similar muscle in Pipa commented upon by myself 2. I need not therefore again refer to the matter. The Cucullaris is a distinctly oblong muscle when seen before raising the supra-scapula. Its fibres, however, converge beneath the scapula into a long flat tendon, which is inserted into the scapular edge near to its posterior boundary, and where it is also widest. The left supra-scapula here deeply overlaps the right; the muscle, therefore, of the left side is dorsal to the right supra-scapula. The Rhomboideus is a small delicate muscle arising by an oblique origin, which touches the middle line of the back anteriorly and diverges posteriorly ; in its course it crosses the cucullaris on the outer side (i. e. that nearest the arm), and is inserted on to the supra-scapula anteriorly. The muscles are of course completely covered by the supra-scapula. The infra-spinatus is entirely covered by the latissimus dorsi; and when this is removed its posterior half is seen to be concealed by the transversus. It is not a double muscle as in Pipa; but its line of origin is shaped like the figure 3, being indented in the middle; it does not anywhere reach the border of the supra-scapula. It is inserted in common with the latissimus dorsi. The Mylohyoid appears to be entirely similar to the same muscle in the C o m m o n Frog. The Pectoralis consists of the three usual divisions. The portio sternalis anterior is much larger than the posterior; the origin of these two divisions of the pectoralis is from the entire length of the sternum; they completely cover all underlying muscles. There is no musculus cutaneus pectoris. Of the two muscles which are brought into view by cutting across and reflecting the sternal portion of the pectoralis, the Stemo-radialis is much the larger ; it takes origin from, at least, two-thirds of the sternum, as well as from the epicoracoid; its fibres converge rapidly to form a narrow flat tendon. The Coraco-humeralis is a large muscle; it arises along the whole of the coracoid and also from the end of the sternum. The Triceps femoris consists of the usual three divisions. The Rectus anticus arises from a very narrow tendon, but rapidly swells out into a big muscle which ends in the fascia covering the vastus internus. In Rana guppgi the connection of this muscle is first with the vastus externus. The Semimembranosus is a particularly stout muscle; but it presents no noteworthy particular. Neither does the Biceps femoris. The Adducter longus is covered by the sartorius; it arises by a 1 " Die ventrale Eumpfmuskulatur der anuren Amphibien," Morph. Jahrb., 1895. 2 " O n some Points in the Anatomy of Pipa americana," above, p. 827. |
