The two types of crab mentioned in the crossword solutions are HERMIT and FIDDLER crabs. HERMIT crabs are a type of land-dwelling crab that have an asymmetrical abdomen and a soft, curved shell. They are found in tropical and subtropical regions around the world. FIDDLER crabs are small, semi-terrestrial crabs that live in coastal areas. They are named for their large claw, which is used to make a fiddling motion. Both species of crab are popular in the aquarium trade.