Definitions for "Opesia"
In zooids of anascan Cheilostomata, the opening below the frontal membrane which remains after development of the cryptocyst. (Hayward & Ryland, 1979). Compare area. Figures: Opaeophora, Chondriovelum, Steginoporella, Parellisina
non-calcified area under the frontal membrane, bordered by cryptoyst, allows for operation of zooid hydrostatic system.