Anatrichosoma haycocki sp. n. (Nematoda: Trichuridae) is described from the para cloacal glands of Antechinus swainsonii (Waterhouse, 1840) and A. stuartii Macleay, 1841 (Marsupialia: Dasyuridae) from Nadgee State Forest, New South Wales, Australia. Immature male and female worms occur free in the intestine. A. haycocki is distinguished from other species of Anatrichosoma by the following suite of morphological characters: small size, absence of longi tudinal cuticular striations in both sexes, subterminal constriction of male tail bearing 14 minute papillae and inflation of posterior portion of mature female giving Trichuris-like appearance. It is also characterised by its occurrence in paracloacal glands in a genus of small carnivorous dasyurid marsupial restricted to Australia and New Guinea. Skrjabinocapillaria rodentium Wertheim and Chabaud, 1979 is recognised as a synonym of Ana trichosoma gerbillis (Bernard, 1964). The genus Skrjabinocapillaria Skarbilovitsch, 1946 is placed as a synonym of Capillaria Zeder, 1800, resulting in the new combination for the type species : C. eubursata (Skarbilovitsch, 1946) comb. nov. It is suggested that deep penetration of the female uterus by the male at insemination is a beha vioural feature common to members of the Trichinelloidea and that the morphology of the male reproductive tract reflects the mechanisms of penetration employed by members of each genus. Anatrichosoma haycocki sp. n. (Nematoda : Trichuridae) des glandes paracloacales A'Antechinus spp., et remarques sur Skrjabinocapillaria Skar hilo vitsch.