The New International Encyclopædia/Rhizodontidæ

RHIZ′ODON′TIDÆ (Neo-Lat. nom. pl., from Gk. ῥίζα, rhiza, root + ὁδούς, odous, tooth). A family of carnivorous Paleozoic fishes of the crossopterygian suborder Rhipidistia, in which the median fins are always more or less subdivided by a process of concentration analogous to that prevalent among dipnoans. The notochord was persistent, and the jaws bore many peculiar teeth. These teeth were highly complicated in the Holoptychidæ, less so in the Rhizodontidæ, with a larger central cavity. A well-known example, found in an unusually good state of preservation, is Eusthenopteron Foordi, herewith figured, which abounds in the Devonian rocks of Quebec, and whose pectoral fin has only one stout basal cartilage—an ‘archipterygium.’ All were small fishes. Consult Woodward, Vertebrate Paleontology (Cambridge, 1898).

EUSTHENOPTERON FOORDI.