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Show 1870.] MYOLOGY OF CHAMAELEON PARSONII. 851 A double-bellied muscle (fig. 1, Z), which might be called a superficial temporal, arises posteriorly from the anterior border of the suspensorium. It here forms a delicate sheet of fibres which converge and are implanted into a tendon which passes beneath the strong zygomatic ligament which connects the posterior margin of the orbit with tbe lower end of the suspensorium. Anteriorly other muscular fibres spring from the upper border of the mandible, and passing backwards are inserted into the tendon before mentioned. Temporalis * (fig. 6, T). This muscle is of prodigious size ; and it would be interesting to know what is the use to the Chameleon of so singularly voluminous a temporal. It springs from the whole surface of the temporal fossa, and from the occipital crest, where it appears on the back of the head, having the most anterior part of the longissimus dorsi on its inner side, and the complexus on its outer side. It is inserted into the upper border of the mandible, between tbe coronoid process and the articular surface. I did not find any distinct masseter f. The depressor mandibulee (figs. 1 and 6, D), or digastric, arises from the postero-external margin of the singular occipital crest and of the suspensorium. It is inserted into the posterior end of the mandible. The pterygoids X (figs. 1, 3, and 5, Pt.) are closely united. The external pterygoid is thick and large, arising from the inner side of the much downwardly prolonged pterygoid, and being inserted into the adjacent side of the mandible, between the coronoid process and the angle of the jaw. The internal pterygoid is much smaller, and passes from the outside of the pterygoid to the posterior part of the mandible. II. MUSCLES OF THE HYOID. The genio-hyoid § (figs. 3, 6, and 7, G. H.) arises from the hinder side of the mandible, at and near its symphysis. Passing backward it ends in a delicate fascia (closely connected with the under surface of the basihyal), which also receives the fibres of the sterno-hyoid, the two muscles thus forming a sheet only interrupted by fascia. The cerato-mandibular\\ (figs. 3, 6, and 7, C. M.) arises in common with the last, of which it may be considered a differentiation. It is inserted into the summit of the thyro-hyal or posterior cornu. Levator arcuum (fig. 7, A). A small muscle may perhaps be thus named which springs from the summits of the hyoidean cornua and loses itself in fascia within the lower jaw. Cerato-hyoideus (fig. 7, H). This is a small but thick muscular * See Cuvier, ' L^eons d'Anat. Comp.' 1835, 2nd edition, tome iv. premiere partie, p. 137. . t This agrees with Meckel's observations. Anat. Comp. traduit par Sanson et Schuster, 1838, tome viii. p. 113. { Cuvier, I. c. p. 140; Meckel, I. c. p. 115. § Cuvier, /. c.p. 531 ; Meckel, I. c. p. 141. || Cuvier, /. c. p. 531 ; Meckel, I.e. p. 141. |