It was from an old well in the Tsu, Mie that the first freshwater medusae in Japan were reported. The medusae are treated as a distinct species Craspedacusta iseana (Oka & Hara 1922). Though there has been frequent reports of freshwater medusae in many localities in Japan, all of them were C. sowerbii. (cf. Uchida, 1951 J. Faculty Sci. Hokkaido Univ., Ser. VI Zool. 10, 157-160)
maintained by Toyokawa M.