Abstract
The distribution of a grapsid crab Ilyograpsus nodulosus in Kochi Prefecture, southern Japan is reported on the basis of 239 specimens collected from March 2004 through July 2006. Prior to this study two females from brackish waters of the Kagami River flowing into Urado Estuary represented the occurrence of this species in Kochi Prefectures. The specimens in this study were collected from 14 localities on estuarine intertidal mudflats from middle to western coast of Tosa Bay.