A novel lipid which contained long-chain base, fatty acid, galactose and N-methylamino-ethylphosphonic acid in an equimolar was isolated from the viscera of Turbo cornutus. The method used for the structural elucidation of this lipid were partial acid hydrolysis, alkaline hydrolysis, periodate oxidation and Smith degradation. The structure of break-down products were mainly identified by combined gas chromatography and mass spectrometry. The structure of the novel lipid was determined to be 1-O-[6'-O-(N-methylaminoethyl-phosphonyl) galactopyranosyl] ceramide. Mass spectra of galactose-N-methylaminoethylphospnate and glycerol-N-methylamino-ethylphosphonate are given.