Details of juveniles approximately 1 h after the completion of inversion (late post-inversion stage). cLSM and SEM images of intact or fragmented juveniles. (A) Midsagittal cLSM optical cross-section of a juvenile showing the localization of F-actin (red) with phalloidin-TRITC (see Figure 5F1 for an overview). (B) Midsagittal cLSM optical cross-section of a juvenile showing the localization of both F-actin (red) and nuclei (blue) with a phalloidin-TRITC/DAPI overlay (see Figure 5F3 for an overview). (C) SEM view of the cell monolayer from outside the spheroid; the conspicuous zones of the ECM are the BZ and FZ3, as described in  and ; and at regions where flagella partially broke off during preparation, double-headed arrows highlight the regular distance and orientation of flagellar pairs. Scale bars: (A, B, C) 10 μm. BZ: boundary zone; cLSM: confocal laser scanning microscopy; DAPI: 4',6-diamidino-2-phenylindole dihydrochloride; ECM: extracellular matrix; F-actin: filamentous actin; FZ: flagellar zone; SEM: scanning electron microscopy; TRITC: tetramethylrhodamine B isothiocyanate.