Histological observations were made to reveal the origin of young brooded in the enteron of adultActinia equinafrom Japan. A total of 295 specimens were collected from four rocky intertidal areas of Sagami Bay and eastern Suruga Bay, Pacific coast of Japan, during the period from February 1994 to January 1995. In the enteron of adults, regardless of sex, 910 young individuals were found. Among them, blastulae with a structure resembling a syncytial blastoderm were found. Development of blastulae to young with tentacles was inferred. Early embryos were observed in both sexes all year round, although the spawning season ofA. equinafrom Japan was restricted to early summer. This observation suggests that early embryos observed during the non-spawning season are produced asexually. Somatic embryogenesis is suggested as the mode of asexual reproduction ofA. equinafrom Japan because of the existence of blastulae in the enteron of anemones in both sexes.