Abstract: The present paper deals with eight known and one new species of Ostracoda,which have been found in the samples of littoral plankton collected in different localities of Lake Tunghu Wuchang.The known species are Cypris subglobosa Sawerby,Strandesia uenoi Klie,Dolerocypris sinensis Sars, Dolerocypris pellucida Klie,Cyprinotus uenoi Brehm,Heterocypris van Douwei Brehm,Stenocypris derupta V vra and Stenocypris malcolmsoni(Brady). The diagnosis of the new species is as follows: Strandesia viridis,sp.n. Female—Length 1.10 mm.,height 0.45 mm.,width 0.39 mm. In dorsal view,the animal is spindle shaped,being slightly narrower behind.The greatest width is located near the center and about one-third of the length of the shell.The left valve overlaps the right one at the anterior end. In side view,the shell is elongate kidney-shaped,with the anterior end broadly and the posterior end narrowly rounded.The highest part of the shell is located at the point one-fifth from the anterior end and it is less than one-half of the length. The swimming-setae of the second antennae are well developed,extend- ing to the tips of the claws.The inner masticatory processes of the maxilla bear two spines which are finely toothed.The length of claws on the second leg is equal to the total length of the distal three podomeres of the same ap- pendage.The length of the terminal claw is less than one-half the dorsal margin of the furcal ramus,and the subterminal claw is usually more than half the length of the terminal claw.The dorsal seta has a length over three- fourths of the terminal claw,while the terminal seta is very short. Male—unknown.