In an earlier paper the author separated Bathynella stammeri (Jakobi) (formerly considered a subspecies) from B. natans Vejd. sensu Jakobi and showed that this new species justified the erection of a new subgenus (Antrobathynella) of Bathynella. Study of the morphology of the mandible, and the 8th pereiopod of the male and female, and examination of the chaetotaxy of the uropods have revealed new diagnostic characters which permit the unequivocal separation of B. natans and B. stammeri. A diagnosis of both species is given. The present study is the result of examination of numerous specimens from many stations in Romania and one station in England.