In June, 1941, the Clarence River Heads, north coast of New South Wales, were visited for the purpose of collecting certain marine molluscan material, in particular, Nudibranchia. For some time Mr. A. A. Cameron, of Harwood Island, Clarence River, had forwarded to the Museum marine specimens from this locality, a considerable proportion of which had indicated the presence there of a strong, extra-Australian tropical influence of ecological and zoo-geographical importance. The nudibranch material was particularly interesting in this respect, since the majority of the rare species he had forwarded were collected in a restricted area, the Angourie Pool, a small excavation in the rocky shore shelf at Angourie, a popular fishing spot. The trip was therefore undertaken to investigate the molluscan fauna in that locality, with special attention to the preparation of field notes and colour sketches of the Nudibranchia encountered.