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Show 318 MESSRS. B. C. A. WINDLE AND F. G. PARSONS ON [Mar. 7, from the anterior inferior border and from the inferior angle of the malar, and is inserted into the lower border of the mandible from the angle to midAvay between the angle and the symphysis. The deep layer comes from the lower part of the posterior border of the malar and is inserted into the outer surface of the mandibular ramus. In his elaborate account of the muscles of the face in Myrmecophaga, Owen does not mention any bilamination of the masseter. Iu Dasypus (22) the muscle is distinctly bilaminar. The same condition obtains also in Chlamydophorus (27, 28), Avhere, according to Hyrtl, it is intersected by tendons. In Manis (29, 30) the masseter is thin and unilaminar and arises from a fibrous zygoma. We have no records of its condition in Oryeteropus. Temporal, Buccinator, and Pterygoidei show no points of special interest. Digastric.-In the Bradypodidce this muscle reaches from the paramastoid process to the middle third of the body of the mandible. In 1, 5, and 6 it is described as possessing a slight tendinous intersection opposite the hyoid bone, from the inner side of Avhich intersection is given off a fibrous arcade similar to that met Avith amongst the Sciuridce. In 3 no tendinous intersection was noticed. Cholcepus (9) has a tendinous intersection, though none Avas noticed by Macalister in his specimen. We have no records of the digastric in any of the Myrmecophagidc?. Among the Dasypodidce the digastric is described as monogastric by Macalister, who states that it is attached below the mandible in Dasypus and Tatusia. In our specimen of Dasypus, and in a second which we specially examined Avith reference to this point, the muscle was absent, but it is figured by Cuvier and Laurillard (24) as arising by tendon and inserted by fleshy fibres. In Chlamydophorus, Macalister found a very small digastric passing from the bulla tympani to the mandible, but Hyrtl found none in his specimen of the same animal. In the Manidce the digastric is inserted into the lower jaAV as far as halfway to the symphysis ; it possesses no central tendon (29). In the Orycteropodid.ee (36, 37) the muscle has the same arrangement. Mylo-hyoid.-This muscle is always Avell marked in the Edentates, being especially large in Myrmecophaga, Tamandua, and Manis, in all of AA'hich animals the posterior fibres curve round the sterno-glossi and the part of the tongue into Avhich these are inserted, forming a narroAV tunnel or sheath in Avhich they are enclosed. Sterno-maxillaris, Hyoid, and Thyroid.-The first of these muscles is absent in the Bradypodidce. In Bradypus (1, 5) the latter tAvo are fused as far as the caudal edge of the larynx, at which point a slip is delaminated from the mesial and ventral part of the muscle and continued to the hyoid bone, the greater part of the muscle passing to the thyroid cartilage. In Cholcepus (10) the two muscles have practically the human attachments. In the Myrmecophagidce the sterno-maxillaris is present as a superficial |
