Four new oxygenated diterpenes 1-4 were isolated from the Caribbean sponge Myrmekioderma styx. The structures of these compounds were deduced by ms, uv, ir, 1H- and 13C-nmr, 1H-1H COSY, XHCORR, and COLOC experiments. Compounds 1-4 are lethal to brine shrimp (Artemia salina).