gymnocyst
From ZooTerms (Dictionary of Invertebrate Zoology)
Bryozoa) A simple type of wall morphology that adds exterior walls to the ends of interior walls, thereby separating adjacent zooids that remain in communication through interzooidal pores.
gymnocyst (noun; Greek gymnos, bare; kystis, bladder): 1. (
2. (Bryozoa: Gymnolaemata) In cheilostomates, continuous or partial frontal shield formed by calcification of the zooidal frontal wall or by cuticle covered spots on the frontal wall.