The glycolipids in oyster mantle were extracted with chloroform: methanol (1: 3) and purified by the solvent fractionation method, and silicic acid column chromato-graphy. The lipids eluted with chloroform: methanol (2: 3) and (1: 4) were mucolipids of the globoside type and consisted of fatty acid, sphingosine, and sugar moiety. Sugar moiety was composed of glucose, galactose, fucose, and O-alkyl-fucose as neutral sugar, and glucosaminc as amino sugar. Besides these sugars, an amino sugar phosphate was found as a component of the lipid. Fatty acids consisted of hexadecanoic, heptadecanoic, and octadecanoic acids as major components. In addition to the usual C18-sphingosine, a C16-like sphingosine and an unidentified base were found as long chain bases.