Résumé : Δ 9(12)‐Capnellene‐2β,5α,8β,10α‐tetrol [1], a new sesquiterpene of the capnellene sesquiterpene class has been isolated from the alcyonarian Capnella imbricata. Its structure and relative configuration were determined by X‐ray diffraction analysis. Copyright © 1979 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim