Polypide

The polypide in bryozoans encompasses most of the organs and tissues of each individual zooid. This includes the tentacles, tentacle sheath, U-shaped digestive tract, musculature and nerve cells. It is housed in the zooidal exoskeleton, which in cyclostomes is tubular and in cheilostomes is box-shaped. Polypides can undergo cycles of regression and regeneration, in which the zooid forms a new polypide as the old one accumulates waste and dies.[1]

  1. ^ Bayer, Micha M.; Todd, Christopher D. (1997). "Evidence for Zooid Senescence in the Marine Bryozoan Electra pilosa". Invertebrate Biology. 116 (4): 331–340. doi:10.2307/3226865. ISSN 1077-8306.