Figure 1.

Whole body regeneration (WBR) in the colonial chordate Botrylloides leachi. A: A B. leachi colony with numerous clonal modules; zooids (arrow). Zooids are embedded in a gelatinous sheet of tunic and are interconnected by a network of blood vessels, which terminates in hundreds of blind ampullar termini (arrowheads). B: An experimental fragment of marginal blood vessels immediately after separation from the colony. C: A vessel mass created after seven days, from the aggregation and migration of blood vessels within the tunic embedment. D: A single adult zooid (black arrow) regenerates from the marginal blood vessels after 10–14 days post separation from B. leachi colonies. Regenerated zooids are reproductive and are fully functional with incurrent (black arrowhead) and outcurrent (white arrowhead) siphons. Scale bar = 500 μm.