Time-lapse acquisition of the palleal budding cycle in B. schlosseri. In these time-lapse images we followed the growth and the development of a bud and the replacement of a zooid during a 6 day  cycle. The movie focuses on an adult zooid: its primary buds, secondary buds, and the common vasculature. At the periphery of the colony, the vasculature ends in sausage-shaped protrusions called ampullae, which contract in a synchronized fashion, and act as auxiliary hearts. The zooid heart, digestive system, endostyle and the circulating blood cells can be seen clearly through the semitransparent body of the zooid and the colony vasculature (ventral side). The last part of the video clip shows the primary bud (B1) growing into an adult zooid, taking over the place of its parent, which is destroyed through a massive wave of apoptosis (resorbing zooid). This asexual budding cycle continues throughout the entire life of the colony (images were taken every 30 minutes during 6 days). Z-zooid B1 and B2-primary buds, sb-secondary bud,,amp-ampulla, H-heart, ds-digestive system, end- endostyle, rZ-resorbing zooid.     Botryllus schlosseri vasculature regeneration following ampullectomy .Several ampullae were surgically removed from the periphery of the zooid. See points 1,2,3,4 at the top of the zooid to observe the regeneration of the vasculature and ampullae. Time lapse images were taken every 30 min for a period of 30 h following ampullae removal. Amp: ampullae, bv: blood vessel, numbers: regeneration spots, t: time, h; hours.     A video movie of a beating heart in the primary bud of a B. schlosseri colony. Ventral view stereomicroscope. h-heart, sb-secondry bud, amp-ampulla, bv-blood vessel.