Dictionary of Ichthyology  

epihyal = the deep, endochondral bone at the upper end of the hyoid arch below the interhyal. It joins the hyomandibular and the symplectic through the interhyal, and articulates with the ceratohyal by a suture in some fishes, e.g. Gadidae. May bear a dentigerous plate. Also called dorsal ceratohyal or posterohyal as it is considered to be the dorsal ossification of the ceratohyal. May or may not be homologous with the epal element of the branchial arches.
Visceral arch of Scyllium (= Scyliorhinus), BH = basihyal, C = copula (united basibranchials), E = epihyal, H = hypohyal, HM = hyomandibula, HY = hyoid, K = keratobranchial, P = pharyngobranchial, from Kingsley's "Textbook of Vertebrate Zoology, 1906. Photograph by Brian W. Coad.

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