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Show 1869.] MYOLOGY OF MENOBRANCHUS LATERALIS. 459 Omo-hyoideus (figs. 3, 4, & 5, O. II). This elongated muscle arises from the inner and upper side of the precoracoid cartilage, and passes thence forwards to between the urohyal and first branchial arch. Genio-glossus*. This small muscle arises, on each side, from the posterior surface of the mandibular symphysis, and thence passes outwards and backwards to be inserted into the skin of the mouth. The levatores brunchiarumf are small muscles which pass downwards from the dorsum of each branchial arch respectively to the dorsum of each gill-tuft. The depressores branchiarum\ go from the ventral surface of each branchial arch to the ventral surface of each gill-tuft respectively. Of the adductores branchiarum^, the first goes from the dorsal end of the second branchial arch to the first gill-tuft; the second similarly from the third branchial arch to the second gill-tuft; the third, long and delicate (fig. 3, A. B ) , extends from the angle between the precoracoid and scapular cartilages forwards to the root of the third gill-tuft and dorsal part of the last branchial arch. APPENDICULAR MUSCLES. Pectoral Limb. Trapezius (fig. 3, Tz). This is an exceedingly small muscle, which is placed immediately behind the third adductor branchiarum and levatores arcuum. It arises from the fascia investing the dorsal muscle, and is inserted into the lower half of the anterior margin of the scapula down to its junction with the precoracoidal cartilage. The latissimus dorsi (fig. 3, L. D) is more than twice the size of the trapezius. It arises from the fascia, and ends by coalescing with the upper part of the triceps. The pectoralis (fig. 4, P. 1 & P. 2) is a considerable muscle which arises partly from one of the tendinous intersections of the rectus, partly from a raphe separating it from its fellow of the opposite side, and partly from the under surface of the posterior part of the coracoidal cartilage towards and at its inner margin. It is inserted into the lowest part of the crest of the humerus, immediately above the origin of the biceps. The part arising from the coracoid (P. 2) is slightly separated from the larger and more posteriorly arising portion (P. I). Serratus magnus. This is a thin small muscle springing from the side of the lateral muscular mass beneath the latissimus dorsi. It is inserted into the inner side of the upper part of the scapula. The levator anguli scapulee is a very long and slender muscle. * Fischer, I. c. p. 67. t Fischer, I. c. p. 38, and tab. iii. b, lb', lb", lb'". j L. c. p. 39, and tab. i. fig. 1, db', db", db'". § L. c. p. 39. |