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Show 92 MESSRS. WATSON AND YOUNG ON THE [Jan. 14, The masseter is also very large ; its attachments are as usual in Carnivores. Dr. Murie states that in IL. brunnea " the masseter is clearly divisible into two layers, notwithstanding Meckel's assertion that this is less marked in the Hyaena than in the Cat." H. crocuta bears out the assertion of Meckel. Of the two pterygoid muscles the internal is by far the largest. Arising from the external surface of the pterygoid bone, it is inserted into the ramus of the mandible, as also into its angular process. The external pterygoid arises immediately above the internal, and passes to the neck of the lower jaw. Compared with the internal pterygoid, to which, by reason of an upward direction of its fibres, it is apparently antagonistic, this muscle is very small. Meckel notes a similar condition of the pterygoid in Carnivora generally. The superficial muscles of the external ear are as follows:-zygo-matico- auricularis from the zygoma to base of concha ; temporo-auri-cularis externus, the origin of which is blended with the posterior belly of the occipito-frontalis just in front of the ear, inserted into the anterior margin of the conchal cartilage ; temporo-auricularis in-ternus from the temporal fascia immediately above zygoma to the inner side of concha. Cervico-auricularis (superficial), narrow and riband-like from the ligamentum nuchae to back of concha. Deep cervico-auricularis arises broad and fleshy from the temporal fascia close to the spine of occiput. It is inserted into the projecting part of conchal cartilage. There are also well-marked scuto-auriculares (internal and external), and, in addition, certain intrinsic muscles, of which the best-marked are a vertical muscle of the concha running on the dorsum towards the tip, and two transverse muscles. Sterno-mastoid arises in common with its fellow, to which it remains united for a little distance in front of the prosternum. It divides at once into two parts, of which the larger and internal decussates with the corresponding fibres of the opposite muscle as far forward as the larynx, and is finally inserted into the base of the mastoid process; whilst the smaller and more external part runs forward to end in the deep cervical fascia, and through it is attached to the occiput. This double character of the sterno-mastoid is remarked in H. striata and H. brunnea by Meckel and Murie respectively. It is also figured in the ' Recueil' (pi. 137) of Cuvier and Laurillard. In Civet there is a cleido-mastoid entirely separate from the sterno-mastoid. Digastric, as usual from the temporal bone, passes to the middle third of the inferior border of the lower jaw. The sterno-hyoid and sterno-thyroid muscles arise close together from the thoracic surface of the sternum; quite separate they pass forwards, and have their usual insertions. A thyro-hyoid exists, and has the ordinary attachments ; the crico-thyroideus is well marked. The omohyoid is absent, as in the Cat, Dog, Civet, and apparently in the majority of Carnivores. Meckel, however, affirms its existence as a small muscle in H. striata ; it is not referred to by Murie in 77. brunnea. |