Dictionary of Ichthyology  

basihyal = the cartilage supporting the tongue at the anterior end of the hyal series in Elasmobranchii. It is the anteriormost median endochondral bone of the basibranchial series, joining both branches of the hyoid series and forming the tongue skeleton in Teleostei. Dorsally is may have a dermal tooth plate called the glossohyal. The basihyal does not always ossify, e.g. in Salmonidae. Also called basihyobranchial and dermal basihyal. 
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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