アコヤガイに寄生する二世吸虫に関する研究-IV

Abstract

In order to elucidate the developmental stages of the cercaria belonging to genus Bucephalus commonly found in Japanese pearl oysters, many kinds of fish living in pearl oyster farms, where the pearl oysters were heavily infected with the cercaria, were collected and examined for the presence of trematoda. 1) A species of trematoda was found in the digestive organs of the fishes, Caranx sexfasciatus and C. ignobilis, and its specific name was identified as Bucephalus various MANTER, 19401). 2) This species bears characteristic similar to those of the metacercaria which could be brought up in the body of some other small fishes or its second intermediate hosts by artificial infection of the cercaria as reported in a previous paper4). 3) The trematoda was frequently found in the carangid fish caught in pearl oyster farms heavily infected with the cercaria belonging to genus Bucephalus, while the fish obtained from cercaria-uninfected farms were always free from the trematoda. 4) The season when carangid fish heavily infected with this trematoda is closely related to the maturing season of the cercariae, especially to the time when they leave the host bivalves. Judging from the above-mentioned facts, it can be said that the trematoda, Bucephalus various, found in the carangid fish may be identical with the adult form of the cercaria living in pearl oyster, which has been reported before as Bucephalus margaritae OZAKI et ISHIBASHI, 19342).