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Anatomy and function of the penial twin papillae system of the Helicinae  (Gastropoda: Helicoidea: Helicidae) and description of two new, small Hemicycla species from the laurel forest of the Canary Islands 

. Zootaxa. 1482, 1 (May 2007), 1–23. DOI:https://doi.org/10.11646/zootaxa.1482.1.1.