Dictionary of Ichthyology  

hyoid arch = the arch lying between the gill arches and jaws, with which it is believed homologous and which helps support the floor of the mouth cavity. Composed in teleostomes of the following paired endoskeleton elements: hyomandibula, symplectic, interhyal, ceratohyal and one or two hypohyals which articulate with the basihyal. The prefixes epi-, cerato- and hypo- should not be interpreted as indicating correspondence with branchial elements bearing the same prefix. Posterohyal (epihyal), anterohyal (ceratohyal), dorosohyal (dorsal hypohyal) and ventrohyal (ventral hypohyal) have been coined to avoid this confusion. Some authors eschew the term epihyal and employ for the epihyal and ceratohyal, posterior and anterior or proximal and distal ceratohyal.
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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