Confocal micrographs of the myogenesis in postmetamorphic developmental stages of Aeolidiella stephanieae. Anterior faces upwards and scale bars represent 50 μm in all aspects expect D, in which it equals 200 μm. All aspects are in lateral view except C and D which are in dorsal view. (A) Early juvenile Aeolidiella stephanieae closely after metamorphosis showing the body wall musculature comprising longitudinal (lm), circular (cm) and oblique muscle fibres (om). Note that the larval retractor muscle is still degenerating (open triangle); bm marks the buccal musculature and e the eye. (B) Early juvenile specimen with outer circular, inner longitudinal and intermediate oblique muscles; m marks the mouth. (C) Juvenile stage with cerata (c) and rhinophores (r). (D) The musculature of the growing tentacles and cerata in a late juvenile A. stephanieae comprises longitudinal and transverse muscle fibres. The body wall consists of a tight meshwork of circular, longitudinal and oblique muscle fibres; cn marks the cnidosac and ot the oral tentacle.