Naria lamarckii, common name the Lamarck's cowrie, is a species of sea snail, a cowry, a marine gastropod mollusk in the family Cypraeidae, the cowries.
The shells of these common cowries reach on average 37- of length, with a minimum size of and a maximum size of . The basic color of the oval-shaped, smooth and shiny shells is ochraceous or fulvous, the dorsum shows a clear longitudinal line and it is ocellated with many whitish small spots, while several chestnut or reddish-brown speckles are present on the edges of both sides. The base is mainly whitish, with a long and wide aperture with several teeth. In the living cowries the mantle is well developed, with external antennae.
This species is distributed in the East Africa and in the Indian Ocean along Aldabra, Kenya, Madagascar, the Mascarene Basin, Mauritius, Mozambique, Zanzibar, Réunion, the Seychelles, Tanzania, India, Thailand, Singapore, Indonesia and Philippines.
Living cowries can be encountered in tropical intertidal water or on coral reef up to about of depth. As they fear the light, during the day they usually stay in coral caves or under rocks. At dawn or dusk they start feeding on sponges or coral polyps.