Common Box Crab
Calappa hepatica
Identification: Colour varies, pale olive to olive-grey or olive-yellow, with flecking but not strong markings. Legs hidden under expanded flange at back of shell. To about 50 mm in carapace width.
Habitat and Range: On rocky and coral reefs, on sand or muddy-sand substrates, from shallow subtidal zone to 50 m. Tropical and subtropical Australia; Indo-Pacific from Red Sea to Clipperton Is., east Pacific.