LARVAL TREMATODES FROM AUSTRALIAN 
FRESHWATER MOLLUSCS, PART XI 
By T. HARVEY JOHNSTON AND ANNE C. BECKWITH, UNIVERSITY OF ADELAIDE 
Summary 
Earlier papers in this series have been published in the Transactions of the Royal 
Society of South Australia, 1937-1945. The present contribution deals with the 
morphology of the cercaria and metacercarcia, obtained experimentally, of two 
Strigeate trematodes, as yet unrecognized as adults. The cercariae were obtained from 
gastropods living in the swamps of the lower Murray River, South Australia. These 
are: (1) Cercaria lesson n. sp., from Planorbis isingi Cotton, Limnaca lessoni 
Deshayes, and Simlimnea subaquatilis Tate; the metacercarial stage occurring in 
freshwater leeches, Glossiphonia spp.; the adult being probably an Apatemon. (2) 
Cercaria ameriannae n. sp. from Amerianna pectorosa Conrad; the metacercaria 
occuring in tadpoles of Limnodynastes sp. (experimental) and, precociously, in 
Amerianna pectorosa; the unrecognized adult being a Diplostome, perhaps a 
Tylodelphys. 
