Dynamics of the colonial ascidian, Botryllus schlosseri. The fate of isolated buds

In three series of colonies of B. schlosseri the grown buds with their bud primordial were detached from the parental zooids which were then removed. The connections of the bud with the marginal vessel in the tunic were either maintained (series I) or severed, the vessel being either preserved intact (series II) or fragmented (series III). The extirpation of the adults resulted in a considerable decrease of the growth rate in the three series: many buds were resorbed together with their bud primordial and the surviving ones developed only the dextral bud primordium. The majority of buds in series II re-established connection with the general circulation through a radial vessel arising as a collateral of the marginal vessel; this occurred only occasionally in series III. In both these series the buds, which did not rejoin the general circulation, while regressing showed the capacity to construct external vascular networks which allowed the development of their bud primordial. In this way independent colonial units formed inside the same colonial matrix each with its own temporal growth pattern.