epibranchial bone uncinate process
Epibranchials 1-3 in adults are compound elements formed by the fusion of epibranchial cartilages and the so-called uncinate processes. Posteromedially directed uncinate processes develop on the posterior edge of epibranchials 1-3. These appear as separate centers of chondrification (6.2 mm) that later fuse laterally to the posterior edges of the epibranchial cartilages (6.8 mm).