New species of Cloacina Linstow, 1898 (Nematoda : Strongyloidea) parasiticin the stomach of the quokka, Setonix brachyurus (Marsupialia : Macropodidae), from Western Australia

Six new species of Cloacina Linstow, 1898 are described from the stomach of the quokka, Setonix brachyurus, from Rottnest Is., Western Australia. They are: C. ceres sp. nov., characterised by lip-like inflations of the peri o ral cuticle, oesophageal bosses extending two thirds of the way to the nerv e ring, the deirid posterior to the nerve ring, absence of oesophageal dent icles, a symmetrical buccal capsule, a simple straight vagina and spicules 1.56-1.97 mm in length; C. laius sp. nov., characterised by a dorsoventrall y elongated buccal capsule, six leaf crown elements, a shallow buccal capsu le which is arched anteriorly in lateral views, oesophageal bosses extendin g to the nerve ring, a single dorsal oesophageal denticle, spicules 1.50-1. 97 mm in length and a recurrent vagina; C. circe sp. nov., characterised by a dorsoventrally elongated mouth opening, six leaf crown elements, cephali c papillae which are situated close together and whose tips are deviated me dially, a shallow buccal capsule arched anteriorly, an oesophagus without b osses or denticles, the deirid posterior to the nerve ring, spicules in the range 0.97-1.35 mm and a straight vagina; C. chiron sp. nov., characterise d by a cervical cuticular inflation, cephalic papillae with a long, obtuse distal segment, six leaf crown elements, a symmetrical buccal capsule, a si mple oesophagus without denticles or bosses, spicules in the range 0.55-0.6 5 mm and a straight vagina; C. cadmus sp. nov., characterised by its small size, simple slender oesophagus lacking bosses or denticles, small, symmetr ical buccal capsule, cephalic papillae with the proximal segment longer tha n the distal, six leaf crown elements, spicules in the range 1.31-1.46 mm a nd a straight vagina; C. telemachus sp. nov., characterised by the shape of the cephalic papillae with the distal segment globose and directed mediall y six leaf crown elements, an oesophagus without bosses or denticles, the d eirid posterior to the nerve ring, spicules 2.33 mm long and a straight vag ina.