FIGURE 4 in On spermatophore-producing aquatic microdrile oligochaetes (Annelida: Clitellata)

FIGURE 4. Aktedrilus species forming spermatophores (from Swedish Museum of Natural History collection). A. A. mediterraneus (Erséus, 1980), spermatophore in segment XI. B–C. A. arcticus (Erséus, 1978), histological sections of the male duct. D. A. labeosus (Baker & Erséus, 1982), copulatory bursa and glandular organ. E,F. A. mediterraneus, histological sections of the male duct. Abbreviations: a atrium, cb copulatory bursa, go glandular organ, gr glandular ring, ms male sac, o ovary, sf sperm funnel, sph spermatophore, vd vas deferens.