Muricanthus radix, the radix murex or root murex, is a species of sea snail, a marine gastropod mollusk in the family Muricidae, the murex snails or rock snails.

Distribution: This species can be found in the western Pacific in parts of Central America (Baja California, from Mexico to Peru).

Habitat: These sea snails live along the tropical coasts in shallow waters among intertidal rocks.

 Shells of Muricanthus radix can reach a size of . These large, massive, heavy shells are globose or pear-shaped and very spiny, with a white surface and blackish-brown foliations and spiral elements. The body whorls have six to eleven varices. The aperture is large, broad, ovate and porcelaneous white. The outer edges are strongly dentate. The siphonal canal is moderately long. The operculum is dark brown.

This species is quite similar to Hexaplex nigritus. The shells of these two species mainly differ in the length, width and in the proportion of blackish-brown versus white. Moreover, shells of H. radix are less oblong and show less spines in black.

Biology: Hexaplex radix feeds primarily on clams.