The bird schistosome austrobilharzia terrigalensis from the Great Barrier Reef, Australia.

Austrobilharzia terrigalensis from Egretta sacra and Larus novaehollandiae at Heron Island, Great Barrier Reef, is described. The prosobranch snail Planaxis sulcatus is the natural intermediate host of A. terrigalensis at Heron Island. The life-cycle of A. terrigalensis was worked out using naturally and experimentally infected Planaxis sulcatus and experimentally infected chickens. Experiments to produce a dermatitis with cercariae of A. terrigalensis were negative. Austrobilharzia terrigalensis infects a wide range of natural hosts in Canada, continental United States, Hawaii and Australia, and uses different snail genera belonging to different families as intermediate hosts in different areas. The wide distribution is apparently due to the habits of some hosts which migrate between the northern and southern hemispheres.