Mauritia histrio, common name the harlequin cowry or the stage cowry, is a species of sea snail, a cowry, a marine gastropod mollusk in the family Cypraeidae, the cowries.
These quite common large shell reach on average of length, with a maximum size of and a minimum adult size of . The basic color of the shell is pale brown, with many grey round spots on the dorsum surface and several dark brown marginal spots on the edges. The base is mainly white or pale brown, with a wide aperture and well-developed darker teeth, longer and stronger on the outer side. In the living mollusk the mantle is transparent, with short papillae. Mauritia histrio is quite similar to Cypraea arabica and Mauritia eglantina.
This species is distributed in the Indian Ocean and Western Pacific Ocean, along Aldabra, Chagos, East Africa, Kenya, Madagascar, the Mascarene Basin, Mauritius, Mozambique, Réunion, the Seychelles, Tanzania, North West Australia and Philippines.
Mauritia histrio lives in tropical shallow water. It is nocturnal, hiding during the day under rocks, large blocks or in deep crevices in coral reefs.