Micro-CT was performed to the anterior end of a polychaete (Lumbrineris latreilli). This specimen was fixed in formalin and preserved in 96% ethanol. For this specimen, no contrast agent was used. Scan was performed with a Skyscan 1172 at a voltage of 60kV and 172μΑ without filter for a full rotation of 360o . This specimen was scanned at a medium camera resolution with an exposure time of 1925ms. This scan was performed for the visualization of the specimen (http://zookeys.pensoft.net/articles.php?id=3650). Specimen was provided by Maria Maintanou and scanned by Sarah Faulwetter. The original dataset is available in https://datadryad.org/resource/doi:10.5061/dryad.84m54.