Species of Labiostrongylus are parasitic in the stomachs of macropodid and potoroid marsupials. The subgenus Labiostrongylus (Labiosimplex) is revised in this paper. The species Labiostrongylus (Labiosimplex) australis, L. (Ls.) bancrofti, L. (Ls.) bipapillosus, L. (Ls.) clelandi, L. (Ls.) communis, L. (Ls.) kungi, L. (Ls.) longispicularis, L. (Ls.) petrogale and L. (Ls.) redmondi are redescribed. L. ualabatus is placed as a synonym of L. (Ls.) clelandi. Twelve new species, L. (Ls.) robustus, sp. nov., L. (Ls.) major, sp. nov., L. (Ls.) occidentalis, sp. nov., L. (Ls.) aridus, sp. nov., L. (Ls.) flanneryi, sp. nov., L. (Ls.) thetidis, sp. nov., L. (Ls.) irma, sp. nov., L. (Ls.) thomasae, sp. nov., L. (Ls.) dendrolagi, sp. nov., L. (Ls.) pearsortensis, sp. nov., L. (Ls.) godmani, sp. nov., and L. (Ls.) laterilabellosus, sp. nov., are described. Labiostrongylus spp. 1–4 from Macropus parma and Lagorchestes hirsutus are discussed but not named and a key to the subgenus is given. A list of macropodid and potoroid hosts of species of Labiostrongylus is provided, and an indication of where further host collection is needed to augment taxonomic work on the genus is given.

In H. chrysogaster Geoffroy, from eight Tasmanian localities, two nematode, one acanthocephalan, three cestode and seven trematode species were found; Diphyllobothrium dendriticum representing a new host-parasite record for H. chrysogaster. Two new species are recorded, one in Notocotylus (Trematoda:Notocotylidae) and one in Corynosoma (Acanthocepha1a:Polymorphidae). Two protozoan parasites, Toxoplasma gondii and Sarcocystis sp., were also detected. Pasteurella multocida bite wound infections are also described.

Eighty-one H. chrysogaster from nineteen localities in Victoria and South Australia were examined for helminths. One acanthocephalan Corynosoma stanleyi: and one cestode, Hymenolepis diminuta, were found. Of the trematodes six were identified to species: Echinoparyphium hydromyos, Fibricola minor, F. intermedius, Microphaflus minutus, Maritrema oocysta and Plagiorchis jaenschi; two were placed in the families Heterophyidae, and Psilostomidae, both new locality records; and two new species Notocotylus sp. nov. and Paramonostomum sp. nov. were found. There were six nematode species: Synhimantus australiensis, Antechiniella suffodiax, Antechiniella sp., Woolleya hydromyos as well as Parastrongyloides sp. and a heteroxynematid both new host records. H. diminuta was the most prevalent helminth, with M. minutus and S. australiensis the most prevalent trematode and nematode respectively. A checklist of helminths from H. chrysogaster is given and comparisons between infections of Tasmanian, Victorian and South Australian hosts are made.Thirty-three of these water rats, trapped live in Victoria, were also examined for protozoa. Klossiella hydromyos, Toxoplasma gondii and Sarcocystis sp. were found. Twenty of the Victorian hosts were examined for ectoparasites. Three mites; Paraspeleognathopsis derricki, Murichirus parahydromys, and Radfordia sp.; one tick, Zxodes tasmani; one louse, Hoplopleura bidentata; and three flea species, Acanthopsylla rothschildi and Echidnophaga spp. were found. 0004-959X/90/060657$03 .OO

The northern hairy-nosed wombat Lasiorhinus krefftii is now restricted to a single population of less than 70 individuals at Epping Forest National Park, North Queensland, Australia, and is listed as critically endangered. We examined six trapped animals for ectoparasites, and 197 faecal samples for endoparasites. All ectoparasites (the tick Ambylomma triguttatum, the flea Echidnophaga cornuta and the louse Boopia dubia) were new host records. Nematode eggs and larvae were found in every faecal sample and the number of eggs varied significantly among months sampled. Cestode proglottids were also found. There was no indication that parasites were causing disease and few species were detected. This last remaining population of L. krefftii may be relatively immunologically naïve, and we suggest that removing them from their natural environment to other areas as part of a captive breeding program should be attempted with caution.