External morphology of Calyptraea aurita. a female, without shell and whole, dorsal view b same animal, whole, ventral view c male, foot removed, ventral view. Abbreviations: fd: dorsal surface of foot; ft: foot; gi: gill; ll: left lateral expansion (flan); mb: mantle border; ns: neck “sole”; pd: penis sperm groove; pe: penis; pg: pedal gland anterior furrow; pp: penis papilla; pr: propodium; rl: right lateral expansion (flan); sn: snout–proboscis; te: cephalic tentacle. Scale bar: 10 mm (a, b), 5 mm (c).