Dictionary of Ichthyology  

homocercal = type of tail fin in which the vertebrae generally turn upward at the hind end of the column, but which is externally symmetrical. The fin rays of the caudal are supported by hypaxial elements. Found in most Teleostei.
Tail of a flounder, Paralichthys californicus, from "A Guide to the Study of Fishes" by D. S. Jordan, 1905. Photograph by Brian W. Coad.....more

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