FIGURE 3 in A revision of the genera Galeolaria and Pyrgopolon (Polychaeta: Serpulidae), with discussions on opercular insertion as a character in their taxonomy and relationships, and their zoogeography

FIGURE 3. Dorsal view of anterior end of Pyrgopolon ctenactis (Mørch, 1863) from Station 212, Santa Barbara, Bonaire, collected, determined and presented by ten Hove, BM (NH) 1971:230. Note operculum inserted independently of branchial radioles of both sides, i.e., from the middle of the anterior end of the thorax.