Entemnotrochus rumphii, common name the Rumphius' slit shell, is a species of large sea snail with gills and an operculum, a marine gastropod mollusc in the family Pleurotomariidae, the slit snails.

The color is yellowish-white, with flames of orange or carmine red, and light violet, particularly developed on the body whorl.

The whorls are visibly convex and divided into nearly equal portions by the slit fasciole, which is a little above the middle.

The sculpture is composed of oblique, radiating striae, more prominent on the upper whorls.

The base of the shell is almost smooth, with a slight stride of growth and very fine concentric lines.