Notice of New Genera of Carboniferous Glyptodipterines

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Abstract
Since the publication, in 1861, of Professor Huxley's memoir on the classification of Devonian Fishes, several new genera have been established, and the intervals between some of the families (tabulated at p. 24, Mem. Geol. Surv., Decade x.) thereby diminished. R hizodopsis , Huxley. Fig. 8. The specimens to which this generic name has been given are those whose scales Prof. Williamsen described and figured in the Phil. Trans. 1849, under the name of Holoptychius sauroides , a term which has also been applied to a tooth which it will appear is generically distinct from Holoptychius . The body of this fish tapers to a .point posteriorly; its greatest depth is at the pectoral arch. Head depressed; orbits forward; gape wide, extending behind them. Maxilla in a single piece, furnished with fine, equal, conical teeth; premaxilla not preserved. Mandible straight, deepest posteriorly, expanded at the symphysis; contains teeth of two sizes; the larger, three or four in number, plicate at the base, strong, conical, slightly incurved; the smaller, one-fourth of the size of the preceding, like them strong, conical: the surface of all the teeth above the plicate base is smooth. Jugular plates in two pairs, principal and posterior. No trace of median or lateral plates. The occipital region is closed in by three bones, in froht of which are the parietals in close approximation. The facial bones are not determinable. Operculars large, subquadrate; suboperculars a half smaller, rounded anteriorly. The parietals, operculars, and jugulars are ornamented with fine, parallel or bifurcating ridges. The

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