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Gastropoda - Rissoidae
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If no rank is listed, the taxon is considered an unranked clade in modern classifications. Ranks may be repeated or presented in the wrong order because authors working on different parts of the classification may disagree about how to rank taxa.
|W. F. Ponder 1984||Shell: of medium to large size, ovateconic, with narrow to absent umbilical chink; weak to moderate axial ribs and weak spiral striae; axial ribs (if present) do not extend over base. Base with prominent fasciole. Aperture with simple peristome, prominently channelled and angled anteriorly and posteriorly. Outer lip opisthocline, with weak varix externally; inner lip rather narrow (Figs 67; 68). Protoconch conical, multispiral or paucispiral (about 3 Yz whorls in M. melanoides, about 2 in M. cepula and M.japonica, and I Yz in M. daedala), micro sculpture absent (known only in M. japonica, Fig. 1420).|