Rabbit lenses were incubated in organ culture with14C-galactose for 6, 12 and 20 hours. Gangliosides were extracted using the Folch-Suzuki method, purified by dialysis and analyzed by thin-layer chromatography. Six radioactive bands, including the origin, were observed. Tentative identification of these bands as N-acetylneuraminylgalactosyglucosyl-ceramide (GM3), N-acetylgalactosaminyl-(N-acetylneuraminyl)-galactosylglucosylceramide (GM2), galactosyl-N-acetylgal-actosaminyl-(N-acetylneuraminyl)-galactosylglucosylceramide (GM1), N-acetylneur-aminylgalactosyl-N-acetylgalactosaminyl-(N-acetylneuraminyl)-galactosylglucosyl-ceramide (GD1a), N-acetylneuraminylgalactosyl-N-acetylgalactosaminyl-(N-acetylneuraminyl-N-acetylneuraminyl) -galactos-ylglucosylceramide (GT) was made by comparison with authentic standard gangliosides. Galactose incorporation into GM3and GM2increased during the first 12 hours but decreased during the period from 12 to 20 hours. GD1aand GTincorporated the greatest amount of label during the period from 12 to 20 hours. Incorporation of labeled galactose into GM1was nearly constant during this time period. Specific activities for GM1GM3and GTwere nearly the same at 6 hours and were about half those of GM2and GD1afor the same time period.