Specimens after regenerating for 16 (C), 24 (A,B,D,E) and 36 (F) hours. Anterior facing upwards in all panels. A,B. Live specimens. A. Slightly compressed specimen. Note the thickened transparent tissue on the caudal end of the animal (black arrow). B. Anaesthetised live specimen under coverslip. Note the blunt posterior end. C-F. Horizontal CLSM projections of specimens stained with fluorophore-tagged phalloidin (plane of optical sections perpendicular to DV axis of specimens). C. Posterior end of specimen. D. Whole specimen. E. Posterior end of specimen in D. Note the complete absence of any structures other than muscles and the disorganised pattern of the muscles. F. Ventral projection. Note that this specimen has been cut more anteriorly than the specimens in C, D and E. Abbreviations: ds, digestive syncytium; fo, frontal organ; m, mouth; st, statocyst. Scale bars: A, B 100 μm; C, D, E, F 50 μm.