Setae for Gill-Cleaning and Respiratory-Water Circulation of Ten Species of Japanese Ocypodid Crabs

The setae of gill-cleaning mechanisms and respiratory-water circulation system of ten species of ocypodid crabs are described. Epipodal setae are classified as of four types: anchor-, scale setule-, simple-, and digitate-scale-setule setae. A few short setae are found on the Milne Edwards aperture (MEA) in Ocypode, while long plumo-pappose setae were found on the MEA in Uca. The basal part of the epipod of third maxilliped (EpMp3) is armed with many pappose setae having digitate-scale setules in Uca. On the other hand, only a few setae are found on the basal part of the EpMp3 in Ocypode. The constricted setae were dominant on Müller’s aperture. Setae on these structures were compared with those of previous studies.