The zooid grows upward in a cone that may curve outward as adjacent zooids also broaden with growth. In most Paleozoic bryozoa, as the zooid grows it seals off older parts of its growing tube. The shape of the colony is determined by the pattern of budding by the individual zooids. The current moves outward through the tentacles. Micro-organismic food is trapped in mucous on the tentacles and moves to the mouth, which is at the base of a funnel formed by the tentacles.
Respiration is accomplished by the tentacles.
They are hollow and contain coelomic fluid, which exchanges gasses with the ambient water. Tissue connection among polypides is either direct or by surface epidermis or through mural pores. Gametes are released into the tentacle sheath where they are fertilized by sperm. The parent zooid degenerates after it reproduces. The colonial skeleton is a composite of adjacent zooecia.