In the present paper two species of Hirudinellidae Dollfus, 1932 collected from marine fishes in waters of the Xisha Islands are described. One of them is a known species, Hirudinella beebei Chandler. 1937 and the other is a new species. A key to the species of the genus Hirudinella ( Garsin, 1730)is given. All the mesurements are in mm, excepting ova in μm. The type specimens are deposited in the Institute of Oceanology, Academia Sinica, Qingdao, China.