Regenerative capability of Plexaura flexuosa is investigated in experiments which simulate the injuries caused by predation of the ovulid snail Cyphoma gibbosum: partial or total removal of the coenenchyme from the axial skeleton. Regenerative growth of the coenenchyme is primarily induced by the possibility of linear extension of the axial epithelium; settlement of fleshy algae or e.g. Millepora (firecoral) on the axial skeleton inhibits the recovery of the coenenchyme. Coenenchyme growth is accompanied by evagination of the polyp cavity wall and by increased mesoglea production. The cellular basis for regeneration lies in the migration capability and morphogenetic plasticity of at least two cell types of the coenenchyme epidermis: interstitial cells and “transitional” cells. Repeated removal of re-grown coenenchyme causes a decrease of the polyp density followed by the formation of new polyps. These are formed by an extra-tentacular budding mechanism which has its primordia in the epidermis of the coenenchyme.