Muracypraea mus, common name the mouse cowry, is a species of sea snail, a cowry, a marine gastropod mollusk in the family Cypraeidae, the cowries. This species was once considered to belong to the archaic genus Siphocypraea (which now includes only extinct species). In 2004 it was placed by Meyer in the specifically created genus Muracypraea Woodring, 1957.