The genus Neoscolecithrix is redefined and its situation in the family is discussed. The division of the species of this genus into two groups, "kehleri" and "farrani", is proposed, based on marked differences in the type of the rostrum, in the mandible's gnathobase, in the maxilla 2 and in the legs, especially the fifth leg. Xanthocalanus watersae Grice (1972) is considered a species of Neoscolecithrix. The female and the male of N. caetanoi sp. n., collected off the Brazilian coast at 900 m depth, are described.