Fig. 9. Summary diagram illustrating the temporal coordination of contractions by the aquiferous canals, apical pinacoderm, ostia and osculum, during a single inflation–contraction event in E. muelleri. During the inflation phase, the apical pinacoderm, canals and osculum gradually dilate. The ostia contract for the duration of the inflation phase. The contraction of the apical pinacoderm and canals lead to the full inflation of the osculum and its rapid contraction. Ostia open only after all other components have relaxed.