The pereiopods (walking legs) are smooth and the inner margin of the dactylus (seventh segment) of the second and third pair bear 16 to 20 minute spines.

Its range extends from the Red Sea, Mozambique and South Africa to India, Japan, Guangdong and Taiwan.

It searches out a sponge, often a species of Suberites, and uses its chelae to fashion a piece to the approximate size of its carapace, and then moulds this in place.

If it is unable to find a suitable sponge, it may steal some from another crab, or use a substitute material; an empty bivalve mollusc shell, a bit of rag, some seaweed, leaves or rubbish.

If it later finds some sponge or a more desirable camouflage than it is currently wearing, it will discard the unwanted material and select the preferred one.