Two new cyclic peroxides (1 and 2) and the known metabolite 3 have been fou
nd in the organic extract of the Indian sponge Acarnus bicladotylota. The s
tructure of the new products has been assured by chemical and spectroscopic
methods. The absolute stereochemistry of 1-3 has been determined by Mosher
's method on the semisynthetic derivative 4.