a buccal mass of Goniobranchus albonares, CASIZ 228939 b reproductive system of Goniobranchus albonares, CASIZ 228939 c buccal mass of Goniobranchus preciosus, CASIZ 208574 d reproductive system of Goniobranchus preciosus, CASIZ 208574 e buccal mass of Goniobranchus rubrocornutus, CASIZ 203047 f reproductive system of Goniobranchus rubrocornutus, CASIZ 203047. Abbreviations: am, ampulla; bb, buccal bulb; bc, bursa copulatrix; ej, ejaculatory duct; es, esophagus; fgm, female gland mass; ot, oral tube; p, penis; pr, prostate; ra, radular sac; rs, receptaculum seminis; va, vagina; mu, mucous gland. Scale bars: 0.1 mm (a, b, e, f); 1 mm (c, d).