A snail of the primary host of Clonorchis sinensis, distributed in the Korean Penninsula, has been called Bulimus striatulus (Benson) Shiba 1934, while that of China, the mainland of Asia, and of Japan has been called Parafossarulus manchouricus Bourguigant(Abbott l951, Sugihara l954). Having studied on the external character and radula of the snail collected from nine areas of Korea, including Kimhae, Jinyong, Namji, Ulsan, Kunsan etc.The author has not found any reasonable distinctions which set up different species between Korean species and Chinese or Japanese species although there exists some slight difference.