The chemical constituents of an unidentified colonial zoanthid, Zoanthus sp., were investigated as part of a program to study toxic marine organisms from the Visakhapatnam coast of India. The colonial zoanthid contains alkaloids of a new structural group, with zoanthamine (1) being the first member. The structure of zoanthamine (1) was determined by X-ray crystallographic analysis and has been communicated previously. The structures of zoanthenamine (2) and zoanthamide (3) were elucidated by comparison of their spectral data with those of zoanthamine (1). This paper reports details of the isolation of zoanthamine (1), zoanthenamine (2), and zoanthamide (3) and proposes structures for the latter two compounds based on interpretation of spectral data. Initial studies indicated that all three compounds inhibit phorbol myristate acetate (PMA) induced inflammation of the mouse ears.