SUMMARYSome 20 species ofArthrobotrysCorda have been listed in the literature. In this study, 8 have been studied from fresh material and the remainder from literary discussions. I have concluded that 12 are valid species, 7 doubtful and 1 a synonym. Two keys, one from pure and one from nematode-infested cultures, have been presented for the separation and identification of the valid species.