FIGURE 6 in New species of aquatic oligochaetes (Annelida: Clitellata) from groundwaters in karstic areas of northern Spain, with taxonomic remarks on Lophochaeta ignota Štolc, 1886

FIGURE 6. Isochaetides freyi (Brinkhurst, 1965). A: histological section of the atrium; B: penial sac with penis lined by cuticle; C: ventral fold of the body wall, where the spermathecal duct opens; D: spermatheca. Abbreviations: a: atrium, c: chaetophore, cps: cuticular penial sheath, p: penis, pg: prostate gland, sa: spermathecal ampulla, sch: spermathecal chaeta, sd: spermathecal duct, vd: vas deferens, vf: ventral fold of the body wall. Scale bars: 100 µm.