The Morphology of Cercariae Obtained from a Snail Host, Semisulcospira Libertina in Japan

Fresh water snails, Semisulcospira libertina, including S reiniana and S. japonica, are known as the first intermediate hosts of pathogenic trematodes, e. g. Paragonimus, Metagonimus, etc. These snails are also infected with many other non-pathogenic cercariae, the majority of which have been described up to now incompletely. Therefore, in the case of epidemiological studies, research workers used to be confused on the differentiation of cercariae. In order to correct such meagre descriptions, the author have already carried out many investigations regarding the morphology of carcariae. More than 18 species of cercariae were detected from Semisulcospira libertine by the author in the past ten years, 1949 to 1959. Ten species of them were already described in details (Ito, 1950, 1952 a, 1952 b, 1953 a, 1953b, 1956, 1958, 1959, 1960). In this paper, another seven species of cercariae are presented and described on their morphological differences; i. e, two furcocercous-, one echinostome-, one xiphidio-, two tailless-, and one cysticercous-cercaria. Among them, four are the redescriptions, while the other three are given a new name respectively.