FIGURE 4. Isochaetides gianii n 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 4. Isochaetides gianii n. sp. A: commissural blood vessels in body segments V and VI; B: anterior end of the body, arrow pointing to the glands on the pharynx, in segment III; C: sudden transition to the intestine, from segments VII to VIII; D: spermatheca; E: detail of spermatheca in a histological section; F: penial sac with penis; G: cross histological section of penial sac; H: longitudinal histological section of penial sac. Abbreviations: ag: accessory gland, cps: cuticular penial sheath, i: intestine, p: penis, rf: ring fold of the penial sac, sa: spermathecal ampulla, sch: spermathecal chaeta, sd: spermathecal duct, sz: spermatozeugmata, vf: ventral fold of the spermatheca. Scale bars: A–D 100 µm, E–H: 50 µm.