Phalloidin-stained tissue in control vs. actin RNAi-treated Ephydatia muelleri. Confocal laser scanning microscopy images of BODIPY 558/568 phalloidin conjugate-stained whole-mount preparations of E. muelleri. A - C. Actin RNAi-treated sponge tissues. D - F. Control-treated sponges. A and D. Arrow shows Actin filament connections to substrate. These connections are generally missing in RNAi-treated tissues. B and E. Arrows show choanocyte chambers while arrowheads point to Actin connections (in endopinacocytes) between chambers, which are largely missing in treated sponges. C and F. Arrowheads show extensive Actin connections between and around choanocyte chambers. These connections are missing or not as extensive in treated tissues.