A chemical investigation of the sponge <i>Verongula</i> cf. <i>rigida</i> led to the isolation of 13 merosesquiterpenes, among which quintaquinone (<b>2</b>), 5-<i>epi</i>-nakijiquinone L (<b>3</b>), and 3-farnesyl-2-hydroxy-5-methoxyquinone (<b>4</b>) were isolated and reported here for the first time. Particularly, compound <b>2</b> is the first member of merosesquiterpenes with a polyketide side chain substituted on C-19. All of the isolated compounds were examined for steroid 5α-reductase inhibitory activity. Cyclospongiaquinone 1 (<b>5</b>) showed a strong activity in the same range as that of standard finasteride.