Four new sulfolipids have been found in the three Fucacea from the coast of Britany P. canaliculata (L) Deen et Thur, F. vesiculosus (L), F. serratus (L). These four polar lipids form a separate group, their structures being very different from those of the glyceride by-products already known. By acid hydrolysis of these substances the aliphatic mono and dialcohols can be separated. The aliphatic hydrocarbons studied by gas chromatography and spectrometric methods (IR, MASS), have been established as being saturated C30 mono or dialcohols, saturated C18 and C20 monoinsaturated dialcohols. SAA are the only substances found: there was no sulfonate or phosphate ester in the three algae studied. The quantity and composition of SAA are not characteristic of the species. Their variations depend on the physiological and biochemical states of the thallus and on the conditions of extraction and purification.