Figure 2 in Towards a phylogeny and evolution of Acochlidia (Mollusca: Gastropoda: Opisthobranchia)

Figure 2. Schematic overview of the cephalic copulatory organs of different acochlidian species. A, Tantulum elegans; B, Hedylopsis spiculifera; C, Pseudunela spp.; D, Strubellia spp. Abbreviations: bf, basal finger; bfg, gland inside basal finger; bs, basal swelling; de, ejaculatory duct; go, copulatory/male genital opening; p, penis; pd, paraprostatic duct; pg, penial gland; ppr, paraprostate; pr, prostate; ps, penial sheath; sg, external sperm groove; st, hollow stylet; th, solid thorn; vd, vas deferens; vdb, back leading vas deferens. Not drawn to scale.