Two main classes of glycosphingolipids are also phospholipids: these comprise the inositol-containing glycophosphosphingolipids (GPSL) and phosphonoglycosphingolipids (PNGSL), containing carbon-phosphorous bonds. Both are unique forms of acidic cell membrane glycosphingolipids. THe GPSL are represented rather ubiquitously in plants, yeast and fungi, and possibly in protozoans, but not in higher animals. The PNGSL have thus far only been found in marine invertebrates, chiefly Aplysia. Despite the possibility that large numbers of novel and unknown structures exist in these two large classes of glycosphingolipids, relatively little structural, biosynthetic and functional work has been accomplished. What is known about GPSLs and PNGSLs will be the subject of this review. © 1986.