Development is primarily the development of a colony and that of the individual zooid is modified accordingly. Each developing zooid or bud gives off in the course of its development a series of four buds from the anterior atrial wall. As each bud disc develops into a vesicle a residual unincorporated region of the disc remains to grow and repeat the process. Budding comes to an end when the growth of the parental zooid nears its close. The development of the bud itself is extremely direct. A disc transforms into a hollow sphere. 2 folds divide this into a central (pharyngeal) and 2 lateral (atrial) chambers. 3 pouches from the middle chamber push out and give rise to heart, neural mass, and intestine. Later development is essentially an elaboration of these unit regions. Buds, at a very early stage, lose their original connection with the parental zooids and acquire an independent connection with the colonial circulatory system. Gonads develop in individual zooids only after the budding phase is passed and when the zooids are in the final active growth phase.