from Wiktionary, Creative Commons Attribution/Share-Alike License
- adj. Of or pertaining to the operculum that covers the gill slits of fish
- n. A branchiostegal ray.
from the GNU version of the Collaborative International Dictionary of English
- adj. Pertaining to the membrane covering the gills of fishes.
from The Century Dictionary and Cyclopedia
- Relating to or of the nature of a branchiostege.
- n. One of the bony rays under the head of a fish below the opercular bones and behind the lower jaw. They are connected by a membrane called the branchiostegal or gill-membrane.
He could reject, with a mere reference to the facts of development, Geoffroy's comparison of the hyoid and the branchiostegal rays in fish with sternum and ribs.
Geoffroy's next step is to point out that the only possible homologues of sternal ribs are the branchiostegal rays, which arise from the large bones of the hyoid arch.
From the hinder edge of the hyoid arch grows out the membranous operculum, in which develop later the opercular bones and branchiostegal rays.
These are the bones connected with respiration -- the operculum, the branchiostegal rays, the branchial arches, and others.