South American shells in the AM collection. All figure pairs show the shell in apertural and dorsal views, unless otherwise noted. A–D. Streptartemon sp., AM MA112083, in apertural, dorsal, apical, and umbilical views, respectively; H = 9.9 mm; E, F. Cerion uva arubanum, probable syntype, AM MA73505; H = 23.2 mm; G, H. Strophocheilus pudicus, AM MA114949; H = 52.4 mm; I, J. Dryptus moritzianus, AM MA114780; H = 73.5 mm; K, L. Plekocheilus alticola, AM MA114947; H = 39.5 mm; M, N. Plekocheilus aurissciuri, AM MA112980; H = 31.5 mm; O, P. Plekocheilus linterae, AM MA114946; H = 42.0 mm. Scale bars: 5 mm (A–F); 2 cm (I, J); 1 cm (G, H, K, L, M, N, O, P).