Figure 8

Three to four chaetigerous ciliary bands: dorsal and lateral view. Scale bars = 50 μm, anterior is to the left. A-F. Phallodin staining (B, E also include anti-acetylated tubulin staining in green and nuclear staining in blue). Prototroch (prot), metatroch (met), ciliary band of peristomium (pcb), ciliary band of chaetigers (BS) and telotroch (tel). C, F. Depth coded (in μm). A-C. Lateral view. In addition to the diagonal ventral longitudinal muscle (dVLM), the outer dorsal longitudinal muscle (oDLM) now extends into the prostomium. The pharynx (phar) is ventrally situated. The ventral longitudinal muscle (VLM) elongates straight posteriorly, whereas inner branches of the dorsal longitudinal muscle (DLM) run dorsomedially toward the midline. The arrowhead marks a circle of transverse muscle anterior to the pygidium. D-F. Dorsal view. Anteriorly, the outer dorsal longitudinal muscles (oDLM) and the ventral diagonal muscle (dVLM) connect within the prostomium, although the median projection of the dVLM (asterisk) remains weakly developed. Inner branches of the dorsal longitudinal muscle (DLM) intersect at the dorsal midline (circle). The anterior (adPM) and posterior dorsal parapodial muscles (pdPM) extend from the dorsal side into the parapodial muscle complex (pmc). The arrowhead marks the transverse muscle circle within the region anterior to the pygidium.