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Show 162 DR. R. Vi. SHUFELDT ON [Apr. 1, described one, and in its characters it almost agrees with the same muscle in Liolepis, as described for us by Sanders. Arising from the summit of the interclavicle and the adjacent fascia, it takes a course directly up the middle of the neck, to become inserted into the basi-hyal and for a limited distance on the adjacent thyro-hyal, on their posterior margins. This muscle is almost in contact with the fellow of the opposite side for its entire length. 14. The Sterno-hyoideus profundus is situated deep to the two last-mentioned muscles, it taking origin from the interclavicle, the corresponding clavicle for nearly its entire length, and from the deep fascia of the neck adjacent to these parts. From this origin its fibres are directed upwards, forwards, and outwards, to finally insert themselves along the hinder border of the thyro-hyal of the same side, from its tip inwardly to the point of insertion of the sterno-hyoideus. At the postero-mesial point of origin this muscle and the fellow of the opposite side are in contact. Muscles of the Shoulder-Girdle and the Upper Extremity. 15. The Sterno-mastoideus in this lizard is a strong, broad, and flat muscle, which arises from the summit of the interclavicle at its external aspect, also from the adjacent fascia as far back as the shoulder-joint. Passing obliquely upwards, forwards, and outwards, it is inserted into the outer end of the squamosal of the corresponding side. At its insertion it is covered by the neuro-mandibularis. Posterior to this the sterno-mastoideus is attached to the superficial fascia overlying the deeper muscles of the back of the neck, as far back as the third cervical vertebra. In this locality the muscle becomes very thin. The anterior and posterior portions of this muscle are somewhat individualized, more especially the dorsal moiety of the muscle, where the cranial aud cervical insertional parts are quite distinct. 16. Trapezius.-This muscle is comparatively feebly developed in Heloderma, being subtriangular in form, and overlapping behind the anterior portion of the latissimus dorsi. It arises as a thin sheet of tendon from the fascia that springs from the cervico-dorsal vertebrae at the summits of their neural spines, from about the last few cervical vertebrae, to include the first two dorsals. The fibres, forming a thin muscular plane, converge as they pass down towards the shoulder-joint, where they again become tendinous, and are finally inserted at the anterior portion of the outer aspect of the suprascapular of the same side, to the fascia below and posterior to this, and more anteriorly to the outer extremity of the corresponding clavicle. 17. Latissimus dorsi is a much better developed muscle than the last described, being a strong, flat, triangular fasciculus of rather coarse muscular fibres, which arise for the most part from the aponeurosis of the dorsum that is attached to the neural spines of tbe tenth to the twenty-first vertebrae inclusive, being adherent to the fascia covering the deeper muscles for some little distance outwards |
