Specimens after regenerating for four days. Anterior facing upwards in A,B,C,D and to the left in E and F. White arrowheads point to bursal nozzle. A-D. Horizontal CLSM projections. A. Ventral side of whole specimen B. Copulatory organs. C. Dorsal part of specimen in B. D. Ventral part of specimen in B. E. Sagittal histological section through female copulatory organ. Note that the seminal bursa (1), the bursal stalk (2) and the vagina (3) are starting to form. F. Sagittal histological section through male copulatory organ. Black arrowhead points to proximal part of penis, where epithelial cells differentiate microvilli on the apical side (densely stained area). Abbreviations: bwn, body-wall musculature; cop, male copulatory organ; cv, chordoid vacuole; ds, digestive syncytium; m, mouth; p, penis; sv, seminal vesicle. Scale bars: A 100 μm; B, E, F 20 μm; C, D 50 μm.