Cryptochiridae is a family of crabs known commonly as gall crabs or coral gall crabs. They live inside dwellings in corals and cause the formation of galls in the coral structure. The family is currently placed in its own superfamily, Cryptochiroidea. Gall crabs are sexually dimorphic, with males much smaller than females. Contrary to females, most males are free-living and "visit" females for mating. The family contains the following twenty-one genera: