A sponge from the Great Barrier Reef is described and placed in a new genus Collospongia of the family Thorectidae, order Dictyoceratida. ln addition to the known scalarane sesterterpenes heteronemin, 12-epi-scalaradial, 12-epi-deacetylscalaradial, 12,18-drepiscalaradial, 12-epi-deoxoscalarin and 12-acet¡l-19,20-dimethoxydeoxoscalarin, the new compounds methyl 18-hydroxy-19-norscalar-16-en-20-carboxylate, 12-deacetylhyrtial, scalarolide acetate and 20-hydroxyscalarolide have
been isolated from this new sponge, Collospongia auris.