Figure 4 from: Liu H-L, Lin D-H, Wang A-T, Hu Z-L, Zhang Y (2024) Description of a new marine flatworm of Prosthiostomum (Platyhelminthes, Polycladida, Prosthiostomidae) from the South China Sea. Zoosystematics and Evolution 100(2): 437-445. https://doi.org/10.3897/zse.100.114482