A novel series of glycosphingolipids containing choline phosphate has been demonstrated in whole tissues of the earthworm, Pheretima hilgendorfi. The thin layer chromatographic pattern of the total polar glycolipids revealed the presence of more than three components with positive reactions toward orcinol-sulfuric acid (sugar), molybdate (phosphate), and Dragendorff's (choline) spray reagents. Two of these polar glycolipids (PGL1 and PGL2) were purified by the use of successive column chromatography on QAE-Sephadex A-25 and silicic acid (Iatrobeads) and detected during elution by the presence of galactose-bound choline phosphate. The structural elucidation of the oligosaccharide moieties was performed by compositional sugar analysis, hydrogen fluoride degradation, proton magnetic resonance spectroscopy, fast atom bombardment mass spectrometry, and methylation analysis. Thus, the structures of PGL1 and PGL2 were deduced to be as follows: cholinephosphoryl-->6Gal beta 1-1Cer and cholinephosphoryl-->6Gal beta 1-6Gal beta 1-1Cer. Although the oligosaccharide structures of both PGL1 and PGL2 have previously been found in other organisms, the presence of a choline phosphate group as an oligosaccharide substituent is the first finding in nature. The main molecular species of the ceramide moieties were composed of beheninyl- and lignocerinyloctadecasphingenines and their nonadecasphingenine homologues.