Early Colony Development inAetea(Bryozoa)

External structures on the erect parts of zooids of Aetea have been demonstrated to be brood chambers by observation of release, settlement and metamorphosis of larvae from the chambers. The ancestrula is smaller than, but very similar to succeeding zooids in the primary zone of astogenetic change, which do not show tubular connections. Sections through brood chambers and zooids show that part of the brood chamber wall may be slightly calcified. Brood chambers appear to be products of the external zooid wall and not diverticula derived from the tentacle sheath.