Scientific report on the Belgian Expedition to the Great Barrier Reef in 1967. Nematodes III. Further study of Desmoscolex -species (Nematoda-Desmoscolecida) from Yonge Reef, Lizard Island and Nymphe Island

2 new spp of Desmoscolex respectively from Lizard Island and Yonge Reef are described: D. asetosus sp. nov.characterized by the absence of cephalic setae and by the presence of elongated amphids; D. paraleptus sp.nov. close to D. leptus Steiner, 1961, but different from it by the presence of the typical setal pattern of 17-ring spp and by the elongated spinnerent. One sberrant specimen near to D. asetosus sp.nov.was found. D. leptus Steiner, 1961 and D. nudus chitwood, 1951 are redescribed.