a. [ Gr. &unr_; gill + &unr_; 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. [ 1913 Webster ]

☞ This term was formerly applied to a group of fishes having boneless branchiæ. But the arrangement was artificial, and has been rejected. [ 1913 Webster ]