epihexodon, Entosphenus Gill [T. N.] 1862:331 [Proceedings of the Academy of Natural Sciences of Philadelphia v. 14; ref. 1668] Based on Petromyzon tridentatus of Girard (not Richardson [= Gairdner]); no description and no reference given for Girard; regarded as not sufficiently tied to a previous reference; not available. •In the synonymy of Entosphenus tridentatus (Richardson 1836). Nomen Nudum. Current status: Synonym of Entosphenus tridentatus (Richardson 1836). Petromyzontidae.