Old measurements of the Stokes polarization parameters for the Jovian decametric radio emission are reexamined for comparison with the broadband measuremens for Io-A and Io-B emission, published recently by the Decametric Radio Astronomy Group at the Meudon Observatory. Records of an Io-C source event, recorded in 1966 at 18 MHz, indicate average values of 0.63 and 0.72 for the degrees of circular and linear polarization, respectively, with a mean value of 0.92 for the total polarization fraction and 0.40 for the average axial ratio. These values, which have not previously been published for the Io-C emission, complement and support the Meudon results. Burst-by-burst sequences of the polarization parameters reveal much diversity in the polarization and allow partial circular polarization to be distinguished from pure elliptical. ¿ American Geophysical Union 1992