Abstract—The lipid composition of the central nervous system of some marine vertebrates and two mammalian species (rat and man) was analysed by one‐ and two‐dimensional quantitative thin‐layer chromatography, and the cerebroside fatty acids were analysed by gas chromatography.The concentrations of sphingomyelin and cerebrosides are higher in mammals than in fishes, while no significant differences are observed for other lipid classes.Furthermore, in mammals the ratio between hydroxy and normal fatty acids in the cerebrosides is much higher than in fishes. The cerebrosides of mammals contain more very long chain fatty acids than those of marine vert