FIGURE 4 in Two new genera of Lumbriculidae (Annelida, Clitellata) from North Carolina, USA

FIGURE 4. Pilaridrilus uliginosus, atria and vasa deferentia. A. Vas deferens above and separate from atrial muscle layer, near midpoint of ampulla. B. Vas deferens embedded in atrial muscle layer (between longitudinal and circular layers), near ental end of ampulla. C. Vas deferens embedded in circular muscle layer of atrium near ectal 1/3 of ampulla, near point of entry into lumen (worm directed to left). D. Atrial muscle layers, showing lenticular openings for prostate ducts. E. Prostate glands. F. Prostate duct penetrating both muscle layers; sagittal view. All to the same scale; scale bars: 50 μm.