Catalogue of the fossil fishes in the British Museum (Natural History) .. . -like baseosts, which are sometimesjointed at intervals and bifurcating. The arrangement of thesupports of the caudal fin is not clearly ascertained. Family HOLOPTYCHIID^]. Body fusiform, with cycloidal, deeply-overlapping scales, more orless enamelled. Head and opercular apparatus with well-developedmembrane-bones : parietals large and separate: frontals separate,not fused into a continuous plate with the adjoining elements; noparietal or frontal foramen ; interoperculum absent; jugular platescomprising one large pair
Catalogue of the fossil fishes in the British Museum (Natural History) .. . -like baseosts, which are sometimesjointed at intervals and bifurcating. The arrangement of thesupports of the caudal fin is not clearly ascertained. Family HOLOPTYCHIID^]. Body fusiform, with cycloidal, deeply-overlapping scales, more orless enamelled. Head and opercular apparatus with well-developedmembrane-bones : parietals large and separate: frontals separate,not fused into a continuous plate with the adjoining elements; noparietal or frontal foramen ; interoperculum absent; jugular platescomprising one large pair, flanked on either side by a lateral bone of mandible thin and deep, bearing a series of smallteeth, and with well-developed infradentaries, much bent inwardsbelow; an inner series of few, large, broad, shuttle-shaped bones, PART II. T 322 CROSSOPTEKYGII. each supporting a laniary tooth; a pair of similar teeth on theroof of the mouth, but the marginal upper dentition feeble. Teethconical, with a very small pulp-cavity, of which the walls exhibit Pig. Transverse section of Holoptychian (Dendrodont) Tooth, much magnified;after Pander. complex infoldings, appearing closely intertwined when viewed intransverse section, these producing superficial vertical fins acutely lobate, pelvic fins acutely or obtusely lobate;two remote dorsal fins; anal fin single ; caudal fin diphycercal orheterocercal. The typical Holoptychius is the single genus of this family as yetdefinitely determined. Genus HOLOPTYCHIUS, Agassiz. [Agassiz in Murchisons Silur. Syst. 1839, p. 599 (Holoptychus),and Poiss. Foss. V. G. E. 1844, p. 68.] Syn. Dendrodus, E. Owen, Microscopic Journal, vol. i. 1841, p. 4. Platyynathus, L. Agassiz, Poiss. Foss. V. G. E. 1844, pp. 61, 76. Lamnodus, L. Agassiz, ibid. 1845, p. 83. (?) Sclerolepis, E. von Eichwald, Bull. Soc. Imp. Nat. Moscou, vol. xvii. 1844, p. 828.(?) Apedodus, J. Leidy, Journ. Acad. Nat. Sci. Philad. [2] vol. iii. 1856, p.
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Keywords: ., bookauthorbritishmuseumnaturalh, bookcentury1800, bookdecade1880
