nIsospondylimost primitive teleost fishes; all are soft-finned: salmon; trout; herring; shad; sardines; anchovies; whitefish; smelts; tarpon
Webster's Revised Unabridged Dictionary
n. plIsospondyli(Zoöl) An extensive order of fishes, including the salmons, herrings, and many allied forms.
Century Dictionary and Cyclopedia
isospondyliAn order of physostomous fishes with no precoracoid arch, the scapular arch suspended to the cranium, a symplectic bone, the pterotic and anterior vertebræ simple, and the parietals separated by the supraoccipital. The order includes most malacopterygian fishes.