. On the anatomy of vertebrates. Vertebrates; Anatomy, Comparative; 1866. ANATOMY OF VERTEBRATES. 123 suspensory pedicle of the under jaw of Fishes. Ascending to the higher generalisations of homology, we see in the tympanic pedicle a serial repetition of the palatine bone ; and, in both, the ribs or plcurajjophyses of contiguous vertebra specially modified for the masticatory functions of the arches they support. The mandible, figs. 81, 84, 29, 32, is the lower portion of the arch, being articulated to the hypotymjianics above, and closed by a ligamentous union or bony symphysis with its fell
. On the anatomy of vertebrates. Vertebrates; Anatomy, Comparative; 1866. ANATOMY OF VERTEBRATES. 123 suspensory pedicle of the under jaw of Fishes. Ascending to the higher generalisations of homology, we see in the tympanic pedicle a serial repetition of the palatine bone ; and, in both, the ribs or plcurajjophyses of contiguous vertebra specially modified for the masticatory functions of the arches they support. The mandible, figs. 81, 84, 29, 32, is the lower portion of the arch, being articulated to the hypotymjianics above, and closed by a ligamentous union or bony symphysis with its fellow at its lower end. The term ' ramus' is applied in Anthropotomy to each half C)f the mandible, and each ramus consists of two, three, or more pieces in different fishes. Most commonly it consists of two pieces, one (hasmapophysis proper, 29,) articulated to the suspensory ])edicle, and edentvdous, analogous to the maxillary ; and the other (liannal spine, 32,) completing the arch, and commonly supporting teeth, like the [)remaxillary. In the Cod, and some other fishes, a third small jnece is superadded, at the angle of the jiosterior piece, fig. 75, 30. The dentary, 32, is deeply excavated, and receives a cylindrical cartilage, the remnant of the embryonal hxmal arch, fig. 69 A, d, and the vessels and nerves of the teeth. The Sudis, fig. 88, the Polypterus, and Amia, have the splint- like plate along the inner surface of the ramus, called ' splenial:' it supports teeth and developes a coronoid pro- cess. In both Sudis and Lc- pidosteus there is superadded a small bony piece, ib, 29 a, answering to the surangular in Reptiles. The Diverfjing Appendatje of the tympano-mandibular arch consists of the bones which support the gill-cover, a kind of short and broad fin, the movements of which regulate the passage of the currents through the branchial cavity, opening and closing the branchial aperture on each side of the head. The first of these 'opercular' bones is the preopercular,
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Keywords: ., bookauthorowenrichard18041892, bookcentury1800, bookdecade1860
