Abstract
Three resin casts of the burrow of a stomatopod crustacean, Oratosquilla oratorio, were obtained by diving in the southern part of Ishikari Bay. The casts showed the following common structural features: a U-shaped tunnel with two openings; the burrow crosssection was semi-circular and the floor was flat and smooth; and a constriction was present on the central part of the burrow. The density of individual O. oratoria in the bay, each occupying a burrow, was estimated at 0.285 inds./m^2, from the number of burrow openings on the bottom.
