Two chaetigerous ciliary bands. Scale bars = 50 μm, anterior is to the left. A-E. Phalloidin staining (red) and in A, D anti-acetylated tubulin staining (green). Prototroch (prot), metatroch (met), ciliary band of peristomium (pcb), ciliary bands of chaetigers (BS) and telotroch (tel). A. Ventral view. Square marks region depicted in B. Labeling as in C. B. Close-up from A, ventral view, phalloidin staining, depth coded (in μm). The parapodial muscle anlage (pma) adjacent to the ciliary bands lie sublongitudinally, i.e., internal to the ventral longitudinal muscle (VLM). C. Same embryo as in A. Ventral view, phalloidin staining. The median ventral longitudinal muscle has now formed (mVLM). Its anterior splits, with branches running around each side of the pharyngeal muscles (phar). The ventral longitudinal muscles (VLM) project into the prostomium as the diagonal ventral longitudinal muscles (dVLM) and the straight ventral longitudinal muscles (sVLM) D. Lateral view. The parapodial muscle anlage (pma) runs on the lateral side of the embryo towards posterior. Each ciliary band (BS) lies between a set of parapodial muscle anlagen (pma). Autofluorescent chaetae (ch) are visible. E. Same embryo as in D. Lateral view, phalloidin staining only. The parapodial muscle anlagen (pma) adjacent to ciliary bands span from the ventral longitudinal muscle (VLM) dorsally to the dorsal longitudinal muscle (DLM). The musculature of the pharynx (phar) exhibits a basket-like shape.