FIGURE 5. Hypothetical transformation series represented by known fossil record of Mimomys ("Cromeromys") and Lemmiscus M3s, shown as right side molars. 1: Mimomys hordijki, Zuurland, Early Pleistocene (LBM, no. Z6-2); 2: Mimomys dakotaensis, Java, Early Pleistocene, reversed; 3-4: Mimomys virginianus, Hamilton Cave, Early Pleistocene (after Repenning and Grady, 1988, p.6, fig. 1 B, C); 5: Lemmiscus sp., SAM Cave, Early Pleistocene (after Repenning, 1992: p.35, fig.6 J); 6–7: Kokoweef Cave, Late Pleistocene-Holocene (after Bell and Jass, 2004, p.7, fig.4 A, B, reversed). Scale bar equals 1 mm.