Report on Four Species of Crabs (Crustacea: Decapoda: Brachyura) from Korea

One pilumnoid, Neoactumnus convexus Sakai, 1965, and three xanthoids, Lybia caestifera (Alcock, 1898), Atergatopsis germaini A. Milne-Edwards, 1865, and Platypodia tomentosa (De Man, 1902), are newly recorded in Korean fauna. Korean pilumnoids and xanthoids now consist of fifteen species and twenty species, respectively.