In November 1975 and 1982, two Myxosporidia were found in Psephurus gladius and Acipenser sinensis from Yangtze River. The descriptions are given below: 1. Myxobolus psephurusi sp. nov. (fig. 1-8). Host and locality: Psephurus gladius, Hung Hu (29.degree.30'N, 113.degree.30'E) of Hubei Province. Location: kidney Cyst: oval or elliptical, diameter 50-70 microns. Spore: oval or pyriform in thecal view; fusiform in sutural view; suturalridge is broad and straight. Anterior end is pointed and posterior edge broadly rounded. Intercapsular appendix distinct. Two club-shaped polar capsules are unequal in size. Their coiled filament are well marked and distinct. The sporoplasm contains a large iodinophilous vacuole and two nuclei. 2-4 V-shaped folds at posterior end. Dimensions of fresh specimen: spore length 16.8 (14.4-19.2).mu., width 11 (9.6-12.4).mu.. Large polar capsule 8.5(7.8-9.6).mu. .times. 4.0 (3.6-4.6).mu.; small one 8.0(6.0-9.0).mu. .times. 3.8(3.0-4.0).mu.. 2. Thelohanellus yiduensis sp. nov. (fig. 9-16). Host and locality: Fry of Acipenser sinensis. y-idu (30.degree.30'N, 111.degree.E) of Middle reaches of the Changjiang (Yangtze river). Location: Gill and skin. Vegetative stages: Cyst rounded with trophozoite of different stage and spore. Spore: long oval in thecal and sutural views with a thin and transparent envelope; sutural ridge straight and distinct. Single polar capsule located at 3/5 position of spore length; coiled filament fine and distinct. Two polar capsule nuclei situated at lateral of polar capsule. Sporoplasm contains a relatively large iodinophilic vacuole and two round nuclei. Dimension of fresh spores: spore with envelope length 41.8 (38.69-46.07).mu. width 12.55(10.44-15.53).mu.; spore length 31.53(30.55-33.6).mu., width 9.46(7.89-10.69).mu., polar capsules 21.1(18.33-22.91).mu. .times. 7.59(6.62-8.15).mu.. Type specimens of the two new species are deposited in the Institute of Hydrobiology, Academia Sinica.