The auther examined the distribution of the helminthic parasites, especially intestinal trematodes of man and domestic animals in Okayama district, and came to the following results:
(1 The eggs of Stellantchasmus falcatus were found at 1.5 per. cent. and Pygidiopsis summus at 0.3 per. cent. in the stools of the natives of Okayama district. No human case of these trematodes has yet been recorded in Japan, owing probabely to the fact that the eggs of these trematodes resemble closely those of Clonorchis sinensis. 2) By stool-examination or section were found the eggs resp. worms of Clonorchis sinensis, Paragonimus westermani, Metagonimus yokogawai, *a new species of Metagonimus, Heterophyes nocens, Pygidiopsis summus, Cornatrium fuscatum, Stephanopirumus longus, Echinochasmus perfoliatus and Lepoderma muris in the dogs, and those of Clonorchis sinensis, Paragonimus westermani, *a new species of Metagonimus, Heterophyes nocens, Stellantchasmus falcatus, Echinochasmus perfoliatus und Echinochasmus japonicus in the cats in Okayama Prefecture. 3) It was confirmed by feeding-examination that Mugil cephalus in Okayama district were infested with the encysted larvae of Stellantchasmus falcatus, Pygidiopsis, summus, *a new species of Metagonimus etc., Pseudorasbora parva with those of Clonorchis sinensis, Cornatrium fuscatum, *a new species of Metagonimus etc. and Acheilognathus lanceolatum with those of Clonorchis sinensis, Heterophyes nocens, Echinochasmus perfoliatus etc. The original paper containes a comparative table and microphotographs of the eggs of Clonorchis sinensis, Stellantchasmus falcatus, Pygidiopsis summus, Heterophyes nocens, Metagonimus yokogawai and *a new species of Metagonimus. *This new species will be named Metagonimus takahashii n. sp. by prof. M. Suzuki.