noun. In zoology, a singular small prehensile process, resembling a bird's head, with a movable mandible, which snaps incessantly, found in many of the Polyzoa. Compare flabellarium, vibracularium.

noun. A modified zooid, in some colonial bryozoans, in the form of a beak, that prevents other organisms from settling on the colony

"It is interesting to see two such widely different organs developed from a common origin; and as the moveable lip of the cell serves as a protection to the zooid, there is no difficulty in believing that all the gradations, by which the lip became converted first into the lower mandible of an avicularium and then into an elongated bristle, likewise served as a protection in different ways and under different circumstances."

antennæ  avicularia  branchiæ  carina  cingulate