Four insufficiently described species of ectosymbiotic peritrich ciliates in the family Lagenophryidae that occur on crustacean hosts in Australia and New Guinea are redescribed. These include two species of Operculigera from phreatoicid isopods, one species of Setonophrys from a phreatoicid isopod, and one species of Lagenophrys from a palaemonid shrimp. Two undescribed species of Operculigera, also found on phreatoicid isopods, are described for the first time. Australian species of Operculigera appear to be restricted to phreatoicid hosts. This is unusual because a diverse array of other lagenophryids occur on parastacid crayfish in Australia. Furthermore, species of Operculigera are conspicuous symbionts of parastacids and various freshwater crabs in Chile and Madagascar. In addition to this peculiarity of distribution, the Australian species of Operculigera appear to comprise a morphologically distinct group within the genus.