Laganum fudsiyama Doederlein 

Family: Laganidae

Order: Clypeasteroida

Locality: East China Sea, 120 m,

Dimensions: 70,8 x 64,4 x 21,6 mm


I got this specimen without taxon, but according to its outer shape it is surely Laganum fudsiyama. The food grooves seem to be conspicuously broad, but I have no other denuded specimens for comparision.