Bran′chi‐os″te‐gal (�), a. [Gr. � gill + � to cover: cf. F. branchiostège.] (Anat.) Pertaining to the membrane covering the gills of fishes. — n.(Anat.) A branchiostegal ray. See Illustration of Branchial arches in Appendix.
☞ This term was formerly applied to a group of fishes having boneless branchiæ. But the arrangement was artificial, and has been rejected.