Figure 2 from: Brincalepe Salvador R, Cavallari DC (2020) Taxonomy and distribution of enigmatic "helicoid" Polygyratia Gray, 1847 (Gastropoda, Stylommatophora). Zoosystematics and Evolution 96(1): 91-101. https://doi.org/10.3897/zse.96.51047

Figure 2 Internal lamellae in the shell of Polygyratia polygyrata.A. Broken specimen showing the second set of internal lamellae, FMNH 40632 (FMNH). B–F. CT scan image showing the internal structures of an intact shell (MZSP 129318). B. Whole shell showing the two sets of internal lamellae. C, D. First set of internal lamellae. E, F. Second set of internal lamellae.Scale bar: 2 cm (A, B).